tests: Do not override existing .config from build.sh

This allows the build.sh script to be used to rebuild binaries based on
existing configuration in addition to the initial case of preparing
suitable build configuration.

Signed-hostap: Jouni Malinen <j@w1.fi>

tests/hwsim/build.sh

@@ -5,11 +5,15 @@ set -e
 cd $(dirname $0)
 
 cd ../../wpa_supplicant
-cp ../tests/hwsim/example-wpa_supplicant.config .config
+if [ ! -e .config ]; then
+    cp ../tests/hwsim/example-wpa_supplicant.config .config
+fi
 make clean
 make -j8
 cd ../hostapd
-cp ../tests/hwsim/example-hostapd.config .config
+if [ ! -e .config ]; then
+    cp ../tests/hwsim/example-hostapd.config .config
+fi
 make clean
 make -j8 hostapd hlr_auc_gw
 cd ../wlantest