Packages: systemd and other improvements.

See the following links for details:
https://github.com/nginx/unit/pull/212
https://github.com/nginx/unit/issues/213

Closes #155, closes #212, closes #213.

pkg/rpm/rpmbuild/SOURCES/unit.logrotate

@@ -0,0 +1,10 @@
+/var/log/unit/*.log {
+    missingok
+    nocreate
+    notifempty
+    postrotate
+        if [ -f /var/run/unit/unit.pid ]; then
+            /bin/kill -SIGUSR1 `cat /var/run/unit/unit.pid`
+        fi
+    endscript
+}

pkg/rpm/rpmbuild/SOURCES/unit.service

@@ -1,14 +1,26 @@
+# Modifying this file in-place is not recommended, because changes
+# will be overwritten during package upgrades.  To customize the
+# behaviour, run "systemctl edit unit" to create an override unit.
+
+# For example, to change options given to the unitd binary at startup,
+# create an override unit (as is done by systemctl edit) and enter
+# the following:
+
+#       [Service]
+#       Environment="UNITD_OPTIONS=--log /var/log/unit/unit.log --pid /run/unit/unit.pid"
+
 [Unit]
 Description=NGINX Unit
 Wants=network-online.target
 After=network-online.target
 
 [Service]
-Type=forking
-PIDFile=/run/unit.pid
-EnvironmentFile=-/etc/sysconfig/unit
-ExecStart=/usr/sbin/unitd $UNITD_OPTIONS
+Type=simple
+Environment="UNITD_OPTIONS=--log /var/log/unit/unit.log --pid /run/unit/unit.pid"
+ExecStart=/usr/sbin/unitd $UNITD_OPTIONS --no-daemon
 ExecReload=
+RuntimeDirectory=unit
+RuntimeDirectoryMode=0755
 
 [Install]
 WantedBy=multi-user.target

pkg/rpm/rpmbuild/SOURCES/unit.sysconf

@@ -1 +1 @@
-UNITD_OPTIONS="--log /var/log/unit.log --pid /run/unit.pid"
+UNITD_OPTIONS="--log /var/log/unit/unit.log --pid /var/run/unit/unit.pid"