Also removed warnings about protoc version matching runtime, since this
is no longer supposed to be a problem (starting with 3.0.0-beta-4) and
all our tests ran fine when using protoc 3.0.2 with protobuf runtime
3.1.0.
Fixes#2316
protoc no longer builds in 3.0.0 because auto-download of the gmock zip
now fails. 3.0.2 has a fix to autogen:
bba446bbf2
All that was strictly necessary was to update .travis.yml and
buildscripts/, but it helps our sanity to keep the rest of the protobuf
versions in sync. Lite is left on its existing version, because it did
not see a bump of neither the java library nor the protoc plugin.
Eric Anderson
Kun Zhang
Xiao Hang