We recently noticed failures occuring for the DbaInifile cache storage tests. The errors reported indicated an inability to perform `dba_replace()` operations, with no indication of why this was. On digging through the various DBA documentation on php.net, I discovered that the `dba_replace` and `dba_insert()` functions are only reliable on GDBM and QDBM handlers; any other handler may result in unexpected or unintended behavior. I have tested against flatfile, GDBM, DB4, and GDBM, and none of these show any issues; however, inifile reliably has issues at this point. As such, we can no longer support that version. This patch raises an exception if the inifile handler is provided as a DBA option, and the tests have been modified to ensure that the exception is raised.