Resolve Bundler issue by updating its version prior to installing Ruby gems.
Resolve Bundler issue by updating its version prior to installing Ruby gems.

Also, update Travis CI e-mail notifications.

Signed-off-by: Krzysztof Wilczynski <9bf091559fc98493329f7d619638c79e91ccf029@linux.com>

kwilczynski/ruby-magic,kwilczynski/ruby-magic