Make it so when we get a pkgpanda build error before re-throwing
Make it so when we get a pkgpanda build error before re-throwing

Otherwise the BuildError is stuck in the middle of a big exception which is a
bit harder to parse.

surdy/dcos,dcos/dcos,mesosphere-mergebot/mergebot-test-dcos,lingmann/dcos,mellenburg/dcos,dcos/dcos,amitaekbote/dcos,darkonie/dcos,branden/dcos,mnaboka/dcos,dcos/dcos,surdy/dcos,GoelDeepak/dcos,dcos/dcos,mesosphere-mergebot/dcos,jeid64/dcos,mnaboka/dcos,GoelDeepak/dcos,vishnu2kmohan/dcos,asridharan/dcos,vishnu2kmohan/dcos,xinxian0458/dcos,branden/dcos,vishnu2kmohan/dcos,amitaekbote/dcos,BenWhitehead/dcos,jeid64/dcos,lingmann/dcos,BenWhitehead/dcos,jeid64/dcos,darkonie/dcos,kensipe/dcos,amitaekbote/dcos,mellenburg/dcos,asridharan/dcos,surdy/dcos,darkonie/dcos,dcos/dcos,mesosphere-mergebot/mergebot-test-dcos,mesosphere-mergebot/mergebot-test-dcos,vishnu2kmohan/dcos,mesosphere-mergebot/dcos,asridharan/dcos,kensipe/dcos,lingmann/dcos,branden/dcos,mesosphere-mergebot/dcos,surdy/dcos,xinxian0458/dcos,darkonie/dcos,mnaboka/dcos,mellenburg/dcos,lingmann/dcos,mnaboka/dcos,amitaekbote/dcos,mellenburg/dcos,xinxian0458/dcos,jeid64/dcos,darkonie/dcos,asridharan/dcos,kensipe/dcos,GoelDeepak/dcos,mesosphere-mergebot/mergebot-test-dcos,xinxian0458/dcos,mnaboka/dcos,BenWhitehead/dcos,branden/dcos,BenWhitehead/dcos,kensipe/dcos,GoelDeepak/dcos,mesosphere-mergebot/dcos