Merge branch 'grpc-1.6.6' into 'master'

Use grpc 1.6.6

See merge request gitlab-org/gitlab-ce!14821

Gemfile.lock

@@ -325,6 +325,8 @@ GEM
       representable (~> 3.0)
       retriable (>= 2.0, < 4.0)
     google-protobuf (3.4.1.1)
+    googleapis-common-protos-types (1.0.0)
+      google-protobuf (~> 3.0)
     googleauth (0.5.3)
       faraday (~> 0.12)
       jwt (~> 1.4)
@@ -351,8 +353,9 @@ GEM
       rake
     grape_logging (1.7.0)
       grape
-    grpc (1.6.0)
+    grpc (1.6.6)
       google-protobuf (~> 3.1)
+      googleapis-common-protos-types (~> 1.0.0)
       googleauth (~> 0.5.1)
     haml (4.0.7)
       tilt