make nbd port check more robust

The following change makes the check for the nbd port or named export
more robust.
I wasn't sure whether to include sed in the dracut_install() of
module-setup.sh since net already does that (and nbd depends on that).

diff --git a/modules.d/95nbd/nbdroot.sh b/modules.d/95nbd/nbdroot.sh
index 4d06425..b176a16 100755 (executable)
--- a/modules.d/95nbd/nbdroot.sh
+++ b/modules.d/95nbd/nbdroot.sh
@@ -31,7 +31,7 @@ nbdflags=${root%%:*}
 nbdopts=${root#*:}
 
 # If nbdport not an integer, then assume name based import
-if [ "${nbdport%[0-9]}" = "$nbdport" ]; then
+if [ ! -z $(echo "$nbdport" | sed 's/[0-9]//g') ]; then
     nbdport="-N $nbdport"
 fi