Bye bye openapi (#1081)

* add DateTime sans mgo

* change all uses of strfmt.DateTime to common.DateTime, remove test strfmt usage

* remove api tests, system-test dep on api test

multiple reasons to remove the api tests:

* awkward dependency with fn_go meant generating bindings on a branched fn to
vendor those to test new stuff. this is at a minimum not at all intuitive,
worth it, nor a fun way to spend the finite amount of time we have to live.
* api tests only tested a subset of functionality that the server/ api tests
already test, and we risk having tests where one tests some thing and the
other doesn't. let's not. we have too many test suites as it is, and these
pretty much only test that we updated the fn_go bindings, which is actually a
hassle as noted above and the cli will pretty quickly figure out anyway.
* fn_go relies on openapi, which relies on mgo, which is deprecated and we'd
like to remove as a dependency. openapi is a _huge_ dep built in a NIH
fashion, that cannot simply remove the mgo dep as users may be using it.
we've now stolen their date time and otherwise killed usage of it in fn core,
for fn_go it still exists but that's less of a problem.

* update deps

removals:

* easyjson
* mgo
* go-openapi
* mapstructure
* fn_go
* purell
* go-validator

also, had to lock docker. we shouldn't use docker on master anyway, they
strongly advise against that. had no luck with latest version rev, so i locked
it to what we were using before. until next time.

the rest is just playing dep roulette, those end up removing a ton tho

* fix exec test to work

* account for john le cache

vendor/google.golang.org/grpc/internal/backoff/backoff.go

@@ -0,0 +1,78 @@
+/*
+ *
+ * Copyright 2017 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+// Package backoff implement the backoff strategy for gRPC.
+//
+// This is kept in internal until the gRPC project decides whether or not to
+// allow alternative backoff strategies.
+package backoff
+
+import (
+	"time"
+
+	"google.golang.org/grpc/internal/grpcrand"
+)
+
+// Strategy defines the methodology for backing off after a grpc connection
+// failure.
+//
+type Strategy interface {
+	// Backoff returns the amount of time to wait before the next retry given
+	// the number of consecutive failures.
+	Backoff(retries int) time.Duration
+}
+
+const (
+	// baseDelay is the amount of time to wait before retrying after the first
+	// failure.
+	baseDelay = 1.0 * time.Second
+	// factor is applied to the backoff after each retry.
+	factor = 1.6
+	// jitter provides a range to randomize backoff delays.
+	jitter = 0.2
+)
+
+// Exponential implements exponential backoff algorithm as defined in
+// https://github.com/grpc/grpc/blob/master/doc/connection-backoff.md.
+type Exponential struct {
+	// MaxDelay is the upper bound of backoff delay.
+	MaxDelay time.Duration
+}
+
+// Backoff returns the amount of time to wait before the next retry given the
+// number of retries.
+func (bc Exponential) Backoff(retries int) time.Duration {
+	if retries == 0 {
+		return baseDelay
+	}
+	backoff, max := float64(baseDelay), float64(bc.MaxDelay)
+	for backoff < max && retries > 0 {
+		backoff *= factor
+		retries--
+	}
+	if backoff > max {
+		backoff = max
+	}
+	// Randomize backoff delays so that if a cluster of requests start at
+	// the same time, they won't operate in lockstep.
+	backoff *= 1 + jitter*(grpcrand.Float64()*2-1)
+	if backoff < 0 {
+		return 0
+	}
+	return time.Duration(backoff)
+}