#8127 Fix how we write the .google_authenticator file
The google authenticator PAM module will write the .google_authenticator files with permission 400 (-r--------) and then Allura can't write to it. We also need to write it with 400 or 600 perms, so it is secure for PAM to use it afterwards. And best to do it atomically, with a file rename operation.
db/8127
Looks good, clear to merge.