Normalize provider name to search for gemspec
Normalize provider name to search for gemspec

In many cases, the configuration may hand us the string that does
not match the gemspec file name;
e.g., "opsworks" vs "dpl-ops_works.gemspec".
So we normalize the config value to look for the correct gem to
build.

andyli/travis-build,craigcitro/travis-build,craigcitro/travis-build,andyli/travis-build