treewide: drop shebang from non-executable lib files

This drops the shebang from another bunch of files in various /lib
folders, as these are sourced and the shebang is useless.

Fix execute bit in one case, too.

This should cover almost all trivial cases now, i.e. where /lib is
actually used for library files.

Signed-off-by: Adrian Schmutzler <freifunk@adrianschmutzler.de>

package/base-files/files/lib/upgrade/common.sh

@@ -1,5 +1,3 @@
-#!/bin/sh
-
 RAM_ROOT=/tmp/root
 
 export BACKUP_FILE=sysupgrade.tgz	# file extracted by preinit