Currently the init script in the RPM package uses the following for its path to the PIDFILE.
This means that the PIDFILE variable would pick up the dbpath variable rather than pidfilepath. This won't prevent the start/stop of the server from occurring, nor the creation of the PIDFILE by the MongoD process but does mean that init would not use the location of PIDFILE when stopping the process.
In addition to this both the variables dont allow for the optional spaces between the equals sign and the key/value.
Pull request for this was made by Alexis Midon: https://github.com/mongodb/mongo/pull/410