Repair Windows buildbots after r320792

Windows paths have colons in them, so the regex will fail there. Just
match for any character; the rest of the message will restrict the match
to the path anyway.

git-svn-id: https://llvm.org/svn/llvm-project/lld/trunk@320793 91177308-0d34-0410-b5e6-96231b3b80d8