Fix double free (spotted by Coverity, CID #1965).

Fix double free (spotted by Coverity, CID #1965).
Check if pattern is not null before using it (Coverity defect #1883).
Fix memory leak with hash collision (Coverity defect #1829).
Fix memory leak when bail cases (Coverity defect #1828).
Don't leak directory name (Coverity defect #1827).
reviewed by: plam