tty1 check might happen when / is read-only

From: Daniel Drake <ddrake@brontes3d.com>

When booting our systems for the first time, / is read only at this point.
Ask mount not to modify /etc/mtab

Index: splashutils-gentoo-0.5.2/splash-functions.sh
===================================================================
--- splashutils-gentoo-0.5.2.orig/splash-functions.sh
+++ splashutils-gentoo-0.5.2/splash-functions.sh
@@ -231,17 +231,16 @@ splash_start() {
 			return 1
 		fi
 
-		mount --bind / ${spl_tmpdir}
+		mount -n --bind / ${spl_tmpdir}
 		if [[ ! -c "${spl_tmpdir}/dev/tty1" ]]; then
-			umount ${spl_tmpdir}
-			clear
+			umount -n ${spl_tmpdir}
 			ewarn "The filesystem mounted on / doesn't contain the /dev/tty1 device"
 			ewarn "which is required for the silent splash to function properly."
 			ewarn "Silent splash will not be enabled. Please create the appropriate"
 			ewarn "device file to avoid this message."
 			return 1
 		fi
-		umount ${spl_tmpdir}
+		umount -n ${spl_tmpdir}
 	fi
 
 	# In the unlikely case that there's a splash daemon running -- kill it.