Fix: ospd-openvas depends on mosquitto MQTT broker

Update the ospd-openvas.service file to require a running mosquitto
service.

(cherry picked from commit 096332a)

Author: bjoernricks

config/ospd-openvas.service

@@ -1,8 +1,8 @@
 [Unit]
 Description=OSPd Wrapper for the OpenVAS Scanner (ospd-openvas)
 Documentation=man:ospd-openvas(8) man:openvas(8)
-After=network.target networking.service redis-server@openvas.service
-Wants=redis-server@openvas.service
+After=network.target networking.service redis-server@openvas.service mosquitto.service
+Wants=redis-server@openvas.service mosquitto.service
 ConditionKernelCommandLine=!recovery
 
 [Service]