Two questions that come to mind right out of the gate are what does Xorg.0.log show, now, regarding glesx.so; and, where did the glesx.so.bak file come from? I looked on several systems, both Debian and RedHat/Fedora, and found it on none of them.So after various attempts to keep fglrx running I just decided to delete the /usr/lib/xorg/modules//glesx.so and X started to work suddenly!
root@azkaban:/usr/lib/xorg/modules# file glesx.so.bak
glesx.so.bak: ELF 64-bit LSB shared object, x86-64, version 1 (SYSV), stripped
Sure your system - or at least, your X install - wasn't "pre-trashed"?