ReleaseEngineering/How To/Reset the Try Server

Due to increased usage on tryserver, this is something we need to do approx once a month.

• make sure joduinn has extracted all the logs he needs for blogposts. Its nice, but not required, to do this repo reset at the end of the calendar month, as it makes blogpost work easier.
• Post downtime notices to dev.planning
• File IT bug to delete the try server hg repo, and create a fresh new hg repo cloned from mozilla-central.
  • typically this is done by aravind
• reconfig http://sm-try-master.mozilla.org:8010/waterfall
• reopen tree