[skip ci] Fix CT fail when compiling an EUnit suite
[skip ci] Fix CT fail when compiling an EUnit suite

Yes, this commit message is strange - as well as the behaviour.
./run_ct is compiling all .erl files under test/.
It also picks up files with EUnit tests
and due to different include search path fails to build them.
The error isn't fatal, though, as no tests were to be run from
the particular file in question (it's name didn't end in _SUITE).
Still, let's get rid of the misleading error message.

This commit won't affect test results, so I skip Travis CI.

esl/escalus