recovery, passwd: Use /bin/sh for interactive shells

Use /bin/sh (ash in busybox builds) for interactive shells, not bash.
Preparation for trimming interactive features from bash to reduce size.

Signed-off-by: Jonathon Hall <jonathon.hall@puri.sm>

initrd/etc/functions

@@ -56,9 +56,9 @@ recovery() {
 		sleep 1
 
 		if [ -x /bin/setsid ]; then
-			/bin/setsid -c /bin/bash
+			/bin/setsid -c /bin/sh
 		else
-			/bin/bash
+			/bin/sh
 		fi
 	done
 }

initrd/etc/passwd

@@ -1 +1 @@
-root:x:0:0:root:/:/bin/bash
+root:x:0:0:root:/:/bin/sh