[SQM] Fix sqm_logger to accept empty strings as input

sqm_logger tried tro wait indefinitely if passed an empty string.
This in turn makes sqm-scripts hang. Quoting the input argument in sqm_logger
seems to fix the problem.

Signed-off-by: Sebastian Moeller <moeller0@gmx.de>

net/sqm-scripts/files/usr/lib/sqm/functions.sh

@@ -6,7 +6,7 @@
 
 #improve the logread output
 sqm_logger() {
-    logger -t SQM -s ${1}
+    logger -t SQM -s "${1}"
 }
 
 insmod() {