gluster: fix typo in gluster hooks event option names

Replace "GLuster" with "Gluster" in LocalizedEnums.properties
file for gluster hook add, remove and update options.

Change-Id: I5577938b32f26507e6044b1f4d273588a8e36ce9
Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=1036035
Signed-off-by: Timothy Asir <tjeyasin@redhat.com>