Merge github.com:grpc/grpc into run_gtest

.travis.yml

package.xml

src/core/support/env_linux.c

src/objective-c/tests/GRPCClientTests.m

src/objective-c/tests/InteropTestsLocalSSL.m

src/objective-c/tests/RxLibraryUnitTests.m

test/cpp/util/test_credentials_provider.cc

test/distrib/php/distribtest.php

tools/buildgen/mako_renderer.py