treewide: convert sed -r to posix -E

Signed-off-by: Kevin Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk>

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

@@ -5,7 +5,7 @@ RAM_ROOT=/tmp/root
 export BACKUP_FILE=sysupgrade.tgz	# file extracted by preinit
 
 [ -x /usr/bin/ldd ] || ldd() { LD_TRACE_LOADED_OBJECTS=1 $*; }
-libs() { ldd $* 2>/dev/null | sed -r 's/(.* => )?(.*) .*/\2/'; }
+libs() { ldd $* 2>/dev/null | sed -E 's/(.* => )?(.*) .*/\2/'; }
 
 install_file() { # <file> [ <file> ... ]
 	local target dest dir