Remove stderr redirection from preset/disable calls in scriplets

We don't expect those calls to fail (they should work fine both
with systemd running and without). But if they fail, most likely
some unit is missing or misspelt, which we want to catch.

systemd.spec

@@ -418,7 +418,7 @@ fi
 
 # Services we install by default, and which are controlled by presets.
 if [ $1 -eq 1 ] ; then
-        systemctl preset \
+        systemctl preset --quiet \
                 remote-fs.target \
                 getty@.service \
                 serial-getty@.service \
@@ -427,7 +427,7 @@ if [ $1 -eq 1 ] ; then
                 systemd-networkd.service \
                 systemd-networkd-wait-online.service \
                 systemd-resolved.service \
-                >/dev/null 2>&1 || :
+                >/dev/null || :
 fi
 
 # remove obsolete systemd-readahead file
@@ -435,7 +435,7 @@ rm -f /.readahead > /dev/null 2>&1 || :
 
 %preun
 if [ $1 -eq 0 ] ; then
-        systemctl disable \
+        systemctl disable --quiet \
                 remote-fs.target \
                 getty@.service \
                 serial-getty@.service \
@@ -446,7 +446,7 @@ if [ $1 -eq 0 ] ; then
                 systemd-networkd.service \
                 systemd-networkd-wait-online.service \
                 systemd-resolved.service \
-                >/dev/null 2>&1 || :
+                >/dev/null || :
 
         rm -f /etc/systemd/system/default.target >/dev/null 2>&1 || :
 fi