Avoid systemd_requires as per updated packaging guidelines

There is no need to have them as systemd correctly handles reloading
depending on the transaction ordering (even if systemd is installed
_after_ the package that installs the unit file).

Additionally, this also makes the scriptlets that manually invoke
systemctl conditional on systemctl being present, similar to what
systemd rpm macros do.

mlocate.spec

@@ -3,7 +3,7 @@
 Summary: An utility for finding files by name
 Name: mlocate
 Version: 0.26
-Release: 30%{?dist}
+Release: 31%{?dist}
 License: GPLv2
 URL: https://fedorahosted.org/mlocate/
 Source0: https://fedorahosted.org/releases/m/l/mlocate/mlocate-%{version}.tar.xz
@@ -13,8 +13,6 @@ Source3: mlocate-updatedb.service
 Source4: mlocate-updatedb.timer
 Requires(pre): shadow-utils
 Requires(post): grep, sed
-# standard systemd requires
-%{?systemd_requires}
 BuildRequires: make
 BuildRequires: systemd
 BuildRequires: gcc
@@ -70,7 +68,9 @@ if [ "$VARIANT_ID" = "silverblue" ] || [ -f /run/ostree-booted ]; then
 fi
 
 %systemd_post mlocate-updatedb.timer
-systemctl start mlocate-updatedb.timer
+if [ -x /usr/bin/systemctl ]; then
+    /usr/bin/systemctl start mlocate-updatedb.timer
+fi
 
 %preun
 %systemd_preun mlocate-updatedb.timer
@@ -79,7 +79,9 @@ systemctl start mlocate-updatedb.timer
 %systemd_postun_with_restart mlocate-updatedb.timer
 
 %triggerin -- %{name} < 0.26-11
-/usr/bin/systemctl start mlocate-updatedb.timer
+if [ -x /usr/bin/systemctl ]; then
+    /usr/bin/systemctl start mlocate-updatedb.timer
+fi
 
 %files -f mlocate.lang
 %doc AUTHORS COPYING NEWS README
@@ -94,6 +96,9 @@ systemctl start mlocate-updatedb.timer
 %ghost %attr(0640,root,slocate) %{_localstatedir}/lib/mlocate/mlocate.db
 
 %changelog
+* Fri Oct 01 2021 Kalev Lember <klember@redhat.com> - 0.26-31
+- Avoid systemd_requires as per updated packaging guidelines
+
 * Thu Jul 22 2021 Fedora Release Engineering <releng@fedoraproject.org> - 0.26-30
 - Rebuilt for https://fedoraproject.org/wiki/Fedora_35_Mass_Rebuild