ssh-copy-id: add restorecon call

In certain situations when creating an authorized_key file on a Linux machine
restorecon(1) may need to be called.  Therefore, attempt to run it if it exists.

MFC After:	1 week
Idea from:	https://bugzilla.redhat.com/show_bug.cgi?id=739989

usr.bin/ssh-copy-id/ssh-copy-id.sh

@@ -46,6 +46,9 @@ sendkey() {
 				printf "$alg $key $comment\n" >> "$keyfile" ; \
 			fi ; \
 		done \
+		if [ -x /sbin/restorecon ]; then \
+			/sbin/restorecon -F "$HOME/.ssh/" "$keyfile" >/dev/null 2>&1 || true ; \
+		fi
 	'\' 
 }