Remove failure decorators for FreeBSD bug

The issue described in llvm.org/pr18065 is actually due to FreeBSD bug
theads/186309 [1], which is now fixed in FreeBSD SVN r261354 [2] and will
be merged to release branches shortly.

Diagnosed and fixed by John Wolfe.

[1] http://www.freebsd.org/cgi/query-pr.cgi?pr=186309
[2] http://svnweb.freebsd.org/base?view=revision&revision=261354

llvm-svn: 200648