add missing parameter to gigablast search url

Closes #1293

searx/engines/gigablast.py

@@ -34,6 +34,7 @@ search_string = 'search?{query}'\
     '&qlang={lang}'\
     '&ff={safesearch}'\
     '&rxiec={rxieu}'\
+    '&ulse={ulse}'\
     '&rand={rxikd}'  # current unix timestamp
 
 # specific xpath variables
@@ -64,6 +65,7 @@ def request(query, params):
                                        number_of_results=number_of_results,
                                        rxikd=int(time() * 1000),
                                        rxieu=random.randint(1000000000, 9999999999),
+                                       ulse=random.randint(100000000, 999999999),
                                        lang=language,
                                        safesearch=safesearch)