[#739] Pop extras from query parameters before sending them to Solr

Also move them from the root search params dict to 'extras', so they can
be also be used on GET requests, eg:

http://ckan/api/action/package_search?q=dogs&ext_bbox=1.36,41.13,1.38,41.15

gets transformed to:

{
    'q': 'dogs',
    'extras': {
        'ext_bbox': '1.36,41.13,1.38,41.15'
    }
}

ckan/lib/search/query.py

@@ -358,6 +358,9 @@ def run(self, query):
             query['mm'] = query.get('mm', '2<-1 5<80%')
             query['qf'] = query.get('qf', QUERY_FIELDS)
 
+        # Pop these ones are Solr does not need them
+        query.pop('extras', None)
+
         conn = make_connection()
         log.debug('Package query: %r' % query)
         try:

ckan/logic/action/get.py

@@ -1243,6 +1243,12 @@ def package_search(context, data_dict):
 
     _check_access('package_search', context, data_dict)
 
+    # Move ext_ params to extras and remove them from the root of the search
+    # params, so they don't cause and error
+    data_dict['extras'] = data_dict.get('extras', {})
+    for key in [key for key in data_dict.keys() if key.startswith('ext_')]:
+        data_dict['extras'][key] = data_dict.pop(key)
+
     # check if some extension needs to modify the search params
     for item in plugins.PluginImplementations(plugins.IPackageController):
         data_dict = item.before_search(data_dict)