Clean out our clickhouse-server.service from /etc

packages/clickhouse-server.postinstall

@@ -26,7 +26,7 @@ if [ "$1" = configure ] || [ -n "$not_deb_os" ]; then
 
     ${CLICKHOUSE_GENERIC_PROGRAM} install --user "${CLICKHOUSE_USER}" --group "${CLICKHOUSE_GROUP}" --pid-path "${CLICKHOUSE_PIDDIR}" --config-path "${CLICKHOUSE_CONFDIR}" --binary-path "${CLICKHOUSE_BINDIR}" --log-path "${CLICKHOUSE_LOGDIR}" --data-path "${CLICKHOUSE_DATADIR}"
 
-    if [ -x "/bin/systemctl" ] && [ -f /etc/systemd/system/clickhouse-server.service ] && [ -d /run/systemd/system ]; then
+    if [ -x "/bin/systemctl" ] && [ -f /lib/systemd/system/clickhouse-server.service ] && [ -d /run/systemd/system ]; then
         # if old rc.d service present - remove it
         if [ -x "/etc/init.d/clickhouse-server" ] && [ -x "/usr/sbin/update-rc.d" ]; then
             /usr/sbin/update-rc.d clickhouse-server remove
@@ -44,4 +44,16 @@ if [ "$1" = configure ] || [ -n "$not_deb_os" ]; then
             fi
         fi
     fi
+
+    # /etc/systemd/system/clickhouse-server.service shouldn't be distributed by the package, but it was
+    # here we delete the service file if it was from our package
+    if [ -f /etc/systemd/system/clickhouse-server.service ]; then
+      SHA256=$(sha256sum /etc/systemd/system/clickhouse-server.service | cut -d' ' -f1)
+      for ref_sum in 7769a14773e811a56f67fd70f7960147217f5e68f746010aec96722e24d289bb 22890012047ea84fbfcebd6e291fe2ef2185cbfdd94a0294e13c8bf9959f58f8 b7790ae57156663c723f92e75ac2508453bf0a7b7e8313bb8081da99e5e88cd3 d1dcc1dbe92dab3ae17baa395f36abf1876b4513df272bf021484923e0111eef ac29ddd32a02eb31670bf5f0018c5d8a3cc006ca7ea572dcf717cb42310dcad7 c62d23052532a70115414833b500b266647d3924eb006a6f3eb673ff0d55f8fa b6b200ffb517afc2b9cf9e25ad8a4afdc0dad5a045bddbfb0174f84cc5a959ed; do
+        if [ "$SHA256" = "$ref_sum" ]; then
+          rm /etc/systemd/system/clickhouse-server.service
+          break
+        fi
+      done
+    fi
 fi