Percent signs ("%") and underscores ("_") are not escaped by
mysql_real_escape_string() and are interpreted as wildcards if combined
with "LIKE". Write a wrapper function db_escape_like() and use it where
appropriate.

Note that we already fixed this for the RPC interface in commit
da2ebb66

 but missed the other places.
This patch should fix all remaining flaws reported in FS#26527.

Signed-off-by: Lukas Fleischer <archlinux@cryptocrack.de>
Signed-off-by: Dan McGee <dan@archlinux.org>