Merge r1879370, r1879757, r1879816, r1880404 from trunk:

Merge r1879370, r1879757, r1879816, r1880404 from trunk:

Travis changes:
a) add job to check for empty APLOGNO() macros
b) don't install CPAN stuff if SKIP_TESTING is set
c) don't tail the error_log on test suite failure since it's almost
   always irrelevant shutdown stuff and obscures the actual failures
d) use coloured grep output when showing segfaults to make them obvious in the
   travis error_log output.
   e.g. https://travis-ci.org/github/apache/httpd/jobs/703517978#L2537

Try removing the cached ~/perl5 to reset the broken worker
MPM test job.

Actually clear the cache for the worker MPM (missed in r1879757).

Update some conditions.

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1880407 13f79535-47bb-0310-9956-ffa450edef68