Improve error output of bad lib CI test

Author: theotherjimmy

.travis.yml

@@ -12,7 +12,7 @@ script:
 # The strange command below asserts that there are exactly 0 libraries that do
 # not start with lib
   - |
-    find -name "*.a" -and -not -name "lib*" | tee BUILD/badlibs && [ ! -s BUILD/badlibs ]
+    find -name "*.a" -and -not -name "lib*" | tee BUILD/badlibs | sed -e "s/^/Bad library name found: /" && [ ! -s BUILD/badlibs ]
   - make -C events/equeue test clean
   - PYTHONPATH=. python tools/test/config_test/config_test.py
   - PYTHONPATH=. python tools/test/build_api/build_api_test.py