Remove pdo_ibm from potential driver list

Doctrine will no longer support this driver as of version 2.5.0 due to stability issues, and recommends using the ibm_db2 driver instead.
Apply patch from Alain91  issue #119
Merge branch 'master' of https://github.com/geekwright/XoopsCore
Merge pull request #120 from geekwright/master

A couple of patches
Merge remote-tracking branch 'upstream/master'
clean variable bug