Work around bugs in name resolution in SphinxSE on MySQL 5.5

No existant version of SphinxSE is currently capable of resolving
hostnames in CONNECTION= strings on MySQL 5.5.  As such, default to
127.0.0.1 when configuring the SphinxSE table on MySQL 5.5 or above.
See http://sphinxsearch.com/bugs/view.php?id=1815
Default to 127.0.0.1 in tests to work on MySQL 5.5
Merge branch '4.0/sphinx-on-mysql-5.5' into 4.0-trunk