Clear temporary files before upgrade

src/freedombone-upgrade

@@ -43,6 +43,9 @@ FRIENDS_MIRRORS_PASSWORD=
 MY_MIRRORS_PASSWORD=
 CURRENT_BRANCH=master
 
+# clear temporary files
+rm -rf /tmp/*
+
 UTILS_FILES=/usr/share/${PROJECT_NAME}/utils/${PROJECT_NAME}-utils-*
 for f in $UTILS_FILES
 do