man: drop whitespace from final <programlisting> lines

In the troff output, this doesn't seem to make any difference. But in the
html output, the whitespace is sometimes preserved, creating an additional
gap before the following content. Drop it everywhere to avoid this.

man/systemctl.xml

@@ -192,7 +192,7 @@ NEXT                         LEFT          LAST                         PASSED
 Sun 2017-02-26 18:55:42 EST  1min 14s left Thu 2017-02-23 13:54:44 EST  3 days ago systemd-tmpfiles-clean.timer systemd-tmpfiles-clean.service
 Sun 2017-02-26 20:37:16 EST  1h 42min left Sun 2017-02-26 11:56:36 EST  6h ago     apt-daily.timer              apt-daily.service
 Sun 2017-02-26 20:57:49 EST  2h 3min left  Sun 2017-02-26 11:56:36 EST  6h ago     snapd.refresh.timer          snapd.refresh.service
-            </programlisting>
+</programlisting>
             </para>
 
             <para><emphasis>NEXT</emphasis> shows the next time the timer will run.</para>
@@ -2867,7 +2867,7 @@ Jan 12 10:46:45 example.com bluetoothd[8900]: gatt-time-server: Input/output err
 [Unit]
 AllowedCPUs=7,11
 EOF
-          </programlisting>
+</programlisting>
 
           <para>Multiple drop-ins may be "edited" in this mode; the same contents will be written to all of
           them.</para>