add phab check command to old checkcommands.cfg

since adding a new file into the check_commands
does not make Icinga find the command

so i'm using the old file we always used until
YuviPanda can teach me what the current way should be

honestly, the different places and ways to add them
is a bit confusing

Change-Id: I100dffb5a829aef8183c5e884c392fca857187d2