Merge pull request #3969 from grpc/release-0_11

examples/objective-c/auth_sample/AuthTestService.podspec

examples/objective-c/auth_sample/MakeRPCViewController.m

examples/objective-c/auth_sample/Podfile

examples/objective-c/route_guide/Podfile

examples/objective-c/route_guide/RouteGuide.podspec

include/grpc++/support/sync_stream.h

src/objective-c/GRPCClient/GRPCCall+OAuth2.h

src/objective-c/GRPCClient/GRPCCall+Tests.h

src/objective-c/GRPCClient/GRPCCall.h

src/objective-c/GRPCClient/private/GRPCChannel.h

src/objective-c/GRPCClient/private/GRPCCompletionQueue.h

src/objective-c/GRPCClient/private/GRPCHost.h

src/objective-c/GRPCClient/private/GRPCSecureChannel.h

src/objective-c/GRPCClient/private/GRPCWrappedCall.h

src/objective-c/GRPCClient/private/NSError+GRPC.h

src/objective-c/ProtoRPC/ProtoMethod.h

src/objective-c/RxLibrary/GRXBufferedPipe.h

src/objective-c/RxLibrary/GRXConcurrentWriteable.h

src/objective-c/RxLibrary/GRXForwardingWriter.h

src/objective-c/RxLibrary/GRXImmediateWriter.h