man: drop discouragment of runtime and vendor drop-ins

In certain situations drop-ins in /usr/lib/ are useful, for example when one package
wants to modify the behaviour of another package, or the vendor wants to tweak some
upstream unit without patching.

Drop-ins in /run are useful for testing, and may also be created by systemd itself.

Follow-up for the discussion in #2103.

diff --git a/man/systemd.unit.xml b/man/systemd.unit.xml
index 79bdb2c..a4f5711 100644 (file)
--- a/man/systemd.unit.xml
+++ b/man/systemd.unit.xml
@@ -203,9 +203,7 @@
     <filename>/run/systemd/system</filename> directories. Drop-in files in <filename>/etc</filename>
     take precedence over those in <filename>/run</filename> which in turn take precedence over those
     in <filename>/usr/lib</filename>. Drop-in files under any of these directories take precedence
-    over unit files wherever located.  (Of course, since <filename>/run</filename> is temporary and
-    <filename>/usr/lib</filename> is for vendors, it is unlikely drop-ins should be used in either
-    of those places.)</para>
+    over unit files wherever located.</para>
 
     <!-- Note that we do not document .include here, as we consider it mostly obsolete, and want
          people to use .d/ drop-ins instead. -->