Test if file exists before to execute sed

kconf_update/korganizer-15.08-kickoff.sh

 #!/bin/sh
 
-sed -i "s/\/korganizer.desktop/\/org.kde.korganizer.desktop/" `kf5-config --path config --locate kickoffrc`
+kickoffrcname=`kf5-config --path config --locate kickoffrc`
+if [ -f "$kickoffrcname" ]; then
+   sed -i "s/\/korganizer.desktop/\/org.kde.korganizer.desktop/" $kickoffrcname
+fi