Fix spelling error in post-receive-email hook

Signed-off-by: Richard Fearn <richardfearn@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: richardfearn

contrib/hooks/post-receive-email

@@ -403,7 +403,7 @@ generate_update_branch_email()
 			echo "            \\"
 			echo "             O -- O -- O ($oldrev)"
 			echo ""
-			echo "The removed revisions are not necessarilly gone - if another reference"
+			echo "The removed revisions are not necessarily gone - if another reference"
 			echo "still refers to them they will stay in the repository."
 			rewind_only=1
 		else