Clean up 126 cycle logs

[pascalchevrel]

firefox-android whole history was merged from github to mercurial during this cycle, as a result:

• The logs for this month cycle are huge with 10 years of development merged in
• Github refuses to host the serialized log as it is 52MB instead of a few hundred KB
• parsing the logs top extract bug numbers stats is broken as
  • the commit structure was not the same on Github
  • it takes so long and so much memory that nginx kills the request

[pascalchevrel]

This is done