[analyzer] scan-build: match whitespace instead of word boundaries around flags.

Because neither ' ' nor '-' is alphanumeric, \b won't match between them!
Since in this case we know our output is coming from a -### invocation,
we should always have spaces on both sides of the flag we're trying to match,
"-cc1".

llvm-svn: 204356

clang/tools/scan-build/ccc-analyzer

@@ -150,7 +150,7 @@ sub GetCCArgs {
   close(TO_PARENT);
   my $line;
   while (<FROM_CHILD>) {
-    next if (!/\b-cc1\b/);
+    next if (!/\s-cc1\s/);
     $line = $_;
   }