Use only bash parameter expansion

Small optimization that avoids forking a process to retrieve basename

Change-Id: I4844ba19525d4a3c7d88cfd6d2f3f3896768a113

tools/run_renderspec.sh

@@ -13,6 +13,6 @@ for spec in ${specdir}/**/*.spec.j2; do
     for specstyle in "suse" "fedora"; do
         echo "run ${spec} for ${specstyle}"
         renderspec --spec-style ${specstyle} ${spec} \
-                   -o $WORKSPACE/logs/`basename ${spec}`.${specstyle}
+                   -o $WORKSPACE/logs/${spec##*/}.${specstyle}
     done
 done