Prefer resolvectl over systemd-resolve

The latter is a deprecated compat symlink.

See https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=979264

Signed-off-by: Michael Biebl <biebl@debian.org>

sos/report/plugins/systemd.py

@@ -9,6 +9,7 @@
 # See the LICENSE file in the source distribution for further information.
 
 from sos.report.plugins import Plugin, IndependentPlugin, SoSPredicate
+from sos.utilities import is_executable
 
 
 class Systemd(Plugin, IndependentPlugin):
@@ -47,11 +48,17 @@ def setup(self):
             "timedatectl"
         ])
 
-        # systemd-resolve command starts systemd-resolved service if that
+        # resolvectl command starts systemd-resolved service if that
         # is not running, so gate the commands by this predicate
+        resolvectl_status = 'resolvectl status' \
+            if is_executable('resolvectl') \
+            else 'systemd-resolve --status'
+        resolvectl_statistics = 'resolvectl statistics' \
+            if is_executable('resolvectl') \
+            else 'systemd-resolve --statistics'
         self.add_cmd_output([
-            "systemd-resolve --status",
-            "systemd-resolve --statistics",
+            resolvectl_status,
+            resolvectl_statistics,
         ], pred=SoSPredicate(self, services=["systemd-resolved"]))
 
         self.add_cmd_output("systemd-analyze plot",