Don't lie to systemd about mdadm's status.

Telling systemd that mdadm was started from the initrd
is often a lie and never necessary.  Now that the reshape monitoring
thread handles SIGTERM gracefully it is OK for system to kill
and mdadm that it finds running.

mdmon still have a bit of a question mark over it so I won't remove
the '@' from there just yet.

Signed-off-by: NeilBrown <neilb@suse.de>

mdadm.c

@@ -116,13 +116,6 @@ int main(int argc, char *argv[])
 	ident.container = NULL;
 	ident.member = NULL;
 
-	/*
-	 * set first char of argv[0] to @. This is used by
-	 * systemd to signal that the task was launched from
-	 * initrd/initramfs and should be preserved during shutdown
-	 */
-	argv[0][0] = '@';
-
 	while ((option_index = -1) ,
 	       (opt=getopt_long(argc, argv,
 				shortopt, long_options,