Removed mention of allow_root.
Removed mention of allow_root.

fusermount and the fuse kernel module don't actually know this option.

Cf. http://sourceforge.net/p/fuse/mailman/message/34127030/

GoogleCloudPlatform/gcsfuse,BanzaiMan/gcsfuse,jacobsa/timeutil,GoogleCloudPlatform/gcsfuse,BanzaiMan/gcsfuse,mbrukman/gcsfuse,GoogleCloudPlatform/gcsfuse,jacobsa/ratelimit,kahing/gcsfuse