This fixes an issue with resmon not correctly cleaning up the shared memory
segments when it dies.

Currently no locking is done on the file to prevent reading of a partial
status dump. This needs fixing.

Also, the file is deleted immediately after opening. This deals with the issue
of having a stale file around if resmon dies and also limits the ability of
somebody to inject invalid data into the file.

git-svn-id: https://labs.omniti.com/resmon/branches/resmon2@367 8c0face9-b7db-6ec6-c4b3-d5f7145c7d55