correct systemd requirements

just BuildRequires: systemd is not enough, requirements are also
needed for the scriptlets. %systemd_requires exists to make this
easy, so let's use it.

mlocate.spec

@@ -3,7 +3,7 @@
 Summary: An utility for finding files by name
 Name: mlocate
 Version: 0.26
-Release: 14%{?dist}
+Release: 15%{?dist}
 License: GPLv2
 URL: https://fedorahosted.org/mlocate/
 Group: Applications/System
@@ -14,7 +14,8 @@ Source3: mlocate-updatedb.service
 Source4: mlocate-updatedb.timer
 Requires(pre): shadow-utils
 Requires(post): grep, sed
-BuildRequires: systemd
+# standard systemd requires
+%{systemd_requires}
 Provides: bundled(gnulib)
 Obsoletes: slocate <= 2.7-30
 
@@ -80,6 +81,9 @@ systemctl start mlocate-updatedb.timer
 %ghost %attr(0640,root,slocate) %{_localstatedir}/lib/mlocate/mlocate.db
 
 %changelog
+* Tue Sep 13 2016 Adam Williamson <awilliam@redhat.com> - 0.26-15
+- add correct systemd requirements for scriptlets (using %systemd_requires)
+
 * Fri Mar 18 2016 Michal Sekletar <msekleta@redhat.com> - 0.26-14
 - start timer after the installation (#1278587)
 - make mlocate-updatedb.service of the type simple, systemd will then not wait for its completion (#1282232)