Switch to an updated docker image

[berezovskyi]

See bugzilla/bugzilla#105

The image I produced in https://github.com/berezovskyi/docker-bugzilla-dev no longer builds due to old CentOS rpm repos no longer working.

[berezovskyi]

Would also be good to pull in proper UTF8 support bugzilla/bugzilla#106

[berezovskyi]

From my notes: https://github.com/bugzilla/bugzilla/blob/5.2-docker/Dockerfile