fixed TARGET_PREFIX in find_last_full_backup

Author: Sven Speckmaier

entrypoint

@@ -28,7 +28,7 @@ TARGET_PREFIX="/target"
 DATA_DIRECTORY="/var/lib/mysql"
 
 find_last_full_backup() {
-	FILES=( $(ls -d $TARGET/full-????-??-??-??????) )
+	FILES=( $(ls -d "${TARGET_PREFIX}/"full-????-??-??-??????) )
 	echo ${FILES[-1]}
 }