Fix ./manage.sh robot_tests (#1633)

doi_resolvers / default_doi_resolver were missing in the settings_robots.yml file, so the test server was not able to start (crash). Since the output wasn't displayed, it was not obvious why the Selenium couldn't connect to searx.

manage.sh

@@ -35,7 +35,7 @@ install_geckodriver() {
     if [ -z "$NOTFOUND" ]; then
         return
     fi
-    GECKODRIVER_VERSION="v0.19.1"
+    GECKODRIVER_VERSION="v0.24.0"
     PLATFORM="`python -c "import six; import platform; six.print_(platform.system().lower(), platform.architecture()[0])"`"
     case "$PLATFORM" in
         "linux 32bit" | "linux2 32bit") ARCH="linux32";;