Distribution specific patch, not going upstream

Disable systemd-run if the command is not found.

diff --git a/xpra/scripts/main.py b/xpra/scripts/main.py
index f3aaf7547b..0218de8a98 100755
--- a/xpra/scripts/main.py
+++ b/xpra/scripts/main.py
@@ -470,24 +470,24 @@ def use_systemd_run(s) -> bool:
     if not is_systemd_pid1():
         return False  # pragma: no cover
     # test it:
-    cmd = ["systemd-run", "--quiet"]
-    if getuid() != 0:
-        cmd += ["--user"]
-    cmd += ["--scope", "--", "true"]
-    proc = Popen(cmd, stdout=PIPE, stderr=PIPE, shell=False)
     try:
-        proc.communicate(timeout=2)
-        r = proc.returncode
-    except TimeoutExpired:  # pragma: no cover
-        r = None
-    if r is None:
-        stop_proc(proc, "systemd-run")
-        if proc.poll() is None:
-            try:
-                proc.communicate(timeout=1)
-            except TimeoutExpired:  # pragma: no cover
-                r = None
-    return r == 0
+        cmd = ["systemd-run", "--quiet", "--user", "--scope", "--", "true"]
+        proc = Popen(cmd, stdout=PIPE, stderr=PIPE, shell=False)
+        try:
+            proc.communicate(timeout=2)
+            r = proc.returncode
+        except TimeoutExpired:  # pragma: no cover
+            r = None
+        if r is None:
+            stop_proc(proc, "systemd-run")
+            if proc.poll() is None:
+                try:
+                    proc.communicate(timeout=1)
+                except TimeoutExpired:  # pragma: no cover
+                    r = None
+        return r == 0
+    except FileNotFoundError:
+        return False
 
 
 def verify_gir() -> None: