tests: Fix current log dir symbolic link

Fix updating of the current symbolic link when LOGDIR is already set.
The current symbolic link was only set, if LOGDIR has not been
previously defined. If the user had chosen to cancel the running test
iteration and run it again by running start.sh again, the current
symbolic link was not updated.

Signed-off-by: Eduardo Abinader <eduardo.abinader@openbossa.org>

tests/hwsim/start.sh

@@ -7,13 +7,11 @@ HAPD=$DIR/../../hostapd/hostapd
 HAPD_AS=$DIR/../../hostapd/hostapd
 WLANTEST=$DIR/../../wlantest/wlantest
 HLR_AUC_GW=$DIR/../../hostapd/hlr_auc_gw
+DATE="$(date +%s)"
 
 if [ -z "$LOGDIR" ] ; then
-    DATE="$(date +%s)"
     LOGDIR="$DIR/logs/$DATE"
     mkdir -p $LOGDIR
-    rm -rf $DIR/logs/current
-    ln -sf $DATE $DIR/logs/current
 else
     if [ -e $LOGDIR/alt-wpa_supplicant/wpa_supplicant/wpa_supplicant ]; then
 	WPAS=$LOGDIR/alt-wpa_supplicant/wpa_supplicant/wpa_supplicant
@@ -29,6 +27,11 @@ else
     fi
 fi
 
+if test -w "$DIR/logs" ; then
+    rm -rf $DIR/logs/current
+    ln -sf $DATE $DIR/logs/current
+fi
+
 if groups | tr ' ' "\n" | grep -q ^admin$; then
     GROUP=admin
 else