Build failed with gem installation
It appears that a new gem got added recently and it is making the build fail on CentOS 6 and Debian 7
LoadError: /lib/x86_64-linux-gnu/libc.so.6: version `GLIBC_2.14' not found (required by /opt/gitlab/embedded/lib/ruby/gems/2.3.0/gems/google-protobuf-3.2.0-x86_64-linux/lib/google/protobuf_c.so) - /opt/gitlab/embedded/lib/ruby/gems/2.3.0/gems/google-protobuf-3.2.0-x86_64-linux/lib/google/protobuf_c.so
/var/cache/omnibus/src/gitlab-rails/config/application.rb:5:in `<top (required)>'
/var/cache/omnibus/src/gitlab-rails/Rakefile:5:in `require'
/var/cache/omnibus/src/gitlab-rails/Rakefile:5:in `<top (required)>'
/opt/gitlab/embedded/bin/bundle:22:in `load'
/opt/gitlab/embedded/bin/bundle:22:in `<main>'
LoadError: /lib/x86_64-linux-gnu/libc.so.6: version `GLIBC_2.14' not found (required by /opt/gitlab/embedded/lib/ruby/gems/2.3.0/gems/google-protobuf-3.2.0-x86_64-linux/lib/google/2.3/protobuf_c.so) - /opt/gitlab/embedded/lib/ruby/gems/2.3.0/gems/google-protobuf-3.2.0-x86_64-linux/lib/google/2.3/protobuf_c.so
/var/cache/omnibus/src/gitlab-rails/config/application.rb:5:in `<top (required)>'
/var/cache/omnibus/src/gitlab-rails/Rakefile:5:in `require'
/var/cache/omnibus/src/gitlab-rails/Rakefile:5:in `<top (required)>'
/opt/gitlab/embedded/bin/bundle:22:in `load'
/opt/gitlab/embedded/bin/bundle:22:in `<main>'
(See full trace by running task with --trace)
Observed in https://dev.gitlab.org/gitlab/omnibus-gitlab/builds/844481 and https://dev.gitlab.org/gitlab/omnibus-gitlab/builds/844477