fix fstab-sys module check

If /etc/fstab.sys does not exist installing fstab-sys module will fail.
Fix this by checking use_fstab and fstab_lines as well

Signed-off-by: Dave Young <dyoung@redhat.com>

dracut

@@ -598,7 +598,7 @@ done
 export initdir dracutbasedir dracutmodules drivers \
     fw_dir drivers_dir debug no_kernel kernel_only \
     add_drivers mdadmconf lvmconf filesystems \
-    use_fstab libdir usrlibdir fscks nofscks cttyhack \
+    use_fstab fstab_lines libdir usrlibdir fscks nofscks cttyhack \
     stdloglvl sysloglvl fileloglvl kmsgloglvl logfile \
     debug host_fs_types host_devs sshkey
 

modules.d/95fstab-sys/module-setup.sh

@@ -3,7 +3,7 @@
 # ex: ts=8 sw=4 sts=4 et filetype=sh
 
 check() {
-    test -f /etc/fstab.sys
+    test -f /etc/fstab.sys || [[ -n $use_fstab  ||  -n $fstab_lines ]]
 }
 
 depends() {