start-testsuite.sh: Use shellcheck to harden script

Change-Id: Iaf887da7ad95ba8b1fe93fe6c29f0518961d2fbb
diff --git a/start-testsuite.sh b/start-testsuite.sh
index 83c381e..61bf771 100755
--- a/start-testsuite.sh
+++ b/start-testsuite.sh
@@ -10,7 +10,7 @@
 fi
 
 SUITE=$1
-CFG=`basename $SUITE`.cfg
+CFG=$(basename "$SUITE").cfg
 if [ $# -gt 1 ]; then
 	CFG=$2
 fi
@@ -19,4 +19,4 @@
 	TEST=$3
 fi
 
-LD_LIBRARY_PATH=`dirname $SUITE`:/usr/lib/titan:/usr/ttcn3/lib ttcn3_start $SUITE $CFG $TEST
+LD_LIBRARY_PATH=$(dirname "$SUITE"):/usr/lib/titan:/usr/ttcn3/lib ttcn3_start "$SUITE" "$CFG" "$TEST"