Move one more 'grep' to condition in scriptlets

Do 'if grep SOMETHING SOMEWHERE' instead of just running grep and
then checking $?.

Ticket: ENT-3385
Changelog: None

Author: vpodzime

packaging/common/cfengine-hub/preremove.sh

@@ -39,11 +39,8 @@ case "`package_type`" in
     ;;
 esac
 
-if [ -f "$MAN_CONFIG" ]; then
-  grep -q cfengine "$MAN_CONFIG"
-  if [ $? = "0" ]; then
-    sed -i '/cfengine/d' "$MAN_CONFIG"
-  fi
+if [ -f "$MAN_CONFIG" ] && grep -q cfengine "$MAN_CONFIG"; then
+  sed -i '/cfengine/d' "$MAN_CONFIG"
 fi
 
 #