ensure the cloned repo dir is removed before starting a new clone run

bootstrap.sh

@@ -7,6 +7,11 @@ SCRIPT_DIR=`dirname $SCRIPT_NAME`
 # create libs dir if necessary
 mkdir -p ${SCRIPT_DIR}/libs
 
+# maybe an earlier run of this script failed
+# thus we should remove the libtoxcore-latest dir
+# if exists, otherwise cloning the git repo may fail
+rm -rf ${SCRIPT_DIR}/libs/libtoxcore-latest 
+
 # clone current master of libtoxcore
 git clone https://github.com/irungentoo/toxcore.git ${SCRIPT_DIR}/libs/libtoxcore-latest