Quote variable refs in Bash string comparisons
Quote variable refs in Bash string comparisons

This prevents syntax errors if the string is empty.

amitaekbote/dcos,surdy/dcos,mesosphere-mergebot/dcos,dcos/dcos,amitaekbote/dcos,asridharan/dcos,BenWhitehead/dcos,vishnu2kmohan/dcos,jeid64/dcos,mnaboka/dcos,vishnu2kmohan/dcos,darkonie/dcos,vishnu2kmohan/dcos,mesosphere-mergebot/mergebot-test-dcos,mnaboka/dcos,mellenburg/dcos,branden/dcos,mnaboka/dcos,mesosphere-mergebot/dcos,dcos/dcos,asridharan/dcos,mellenburg/dcos,mesosphere-mergebot/mergebot-test-dcos,amitaekbote/dcos,darkonie/dcos,asridharan/dcos,mesosphere-mergebot/mergebot-test-dcos,darkonie/dcos,surdy/dcos,asridharan/dcos,GoelDeepak/dcos,branden/dcos,kensipe/dcos,BenWhitehead/dcos,jeid64/dcos,mesosphere-mergebot/dcos,mnaboka/dcos,dcos/dcos,lingmann/dcos,vishnu2kmohan/dcos,lingmann/dcos,branden/dcos,amitaekbote/dcos,BenWhitehead/dcos,darkonie/dcos,lingmann/dcos,jeid64/dcos,kensipe/dcos,GoelDeepak/dcos,dcos/dcos,kensipe/dcos,branden/dcos,surdy/dcos,mnaboka/dcos,dcos/dcos,BenWhitehead/dcos,mellenburg/dcos,GoelDeepak/dcos,mesosphere-mergebot/dcos,GoelDeepak/dcos,lingmann/dcos,kensipe/dcos,jeid64/dcos,mellenburg/dcos,mesosphere-mergebot/mergebot-test-dcos,surdy/dcos,darkonie/dcos