imgur: Restrict URL to imgur domains

Otherwise it would crash any pastoob get!

modules/imgur/module.py

@@ -23,6 +23,7 @@ from weboob.capabilities.paste import CapPaste, BasePaste
 from weboob.tools.capabilities.paste import image_mime
 from weboob.capabilities.base import StringField
 from weboob.deprecated.browser import StandardBrowser
+from weboob.deprecated.browser.decorators import check_url
 from urllib import urlencode
 import re
 
@@ -91,6 +92,7 @@ class ImgurModule(Module, CapPaste):
             paste.id = json['data']['id']
             paste.delete_url = 'https://api.imgur.com/3/image/%s' % json['data']['deletehash']
 
+    @check_url('https?://(?:[a-z]+\.)?imgur.com/')
     def get_paste(self, id):
         paste = ImgPaste(id)
         paste.contents = self.browser.readurl(paste.raw_url).encode('base64')