Save stc temp logs in the stc folder

There was an issue when OCN was set to localhost. As part of Net-Smoke,
the command 'mn -c' is run which removes '/tmp/*.log'. This potentially
caused some tests to fail.

Change-Id: If68c184902b994e1ee38ea775c378ce29cdb891f
(cherry picked from commit a67dc45535c7b0b8ea6f246a10c1f2e4e18abb83)
diff --git a/tools/test/bin/stc b/tools/test/bin/stc
index 9334987..8b26ac8 100755
--- a/tools/test/bin/stc
+++ b/tools/test/bin/stc
@@ -12,7 +12,7 @@
 # Download the STC binary if needed
 if [ ! -f $JAR ]; then
     printf "Downloading STC binary..."
-    aux=/tmp/stc-$$.log
+    aux=/tmp/stc/stc-$$.log
     mvn dependency:get -Dartifact=org.onosproject:onos-stc:$VER -Dtransitive=false -B >$aux || fgrep '[ERROR]' $aux
     rm -f $aux
     [ -f $JAR ] && printf "Done.\n"