Fixed issue where validation was giving INVALID_TYPE instead of MISSING_IN_REQUEST if path variable is not present in transaction

lib/schemapack.js

@@ -447,6 +447,8 @@ class SchemaPack {
                 return transactionPathVar.key === pathVar.key;
               });
               pathVar.value = _.get(mappedPathVar, 'value', pathVar.value);
+              // set _varMatched flag which represents if variable was found in transaction or not
+              pathVar._varMatched = !_.isEmpty(mappedPathVar);
             });
 
             // resolve $ref in all parameter objects if present