bridgedb.HTTPServer.ReCaptchaProtectedResource.checkSolution() doesn't expect a deferred

From bridgedb-0.1.5, bridgedb.HTTPServer.ReCaptchaProtectedResource.checkSolution() expects a bool for the solution internal variable, not a t.i.defer.Deferred:

Unhandled Error
Traceback (most recent call last):
  File "/usr/lib/python2.7/dist-packages/twisted/web/http.py", line 1349, in dataReceived
    finishCallback(data[contentLength:])
  File "/usr/lib/python2.7/dist-packages/twisted/web/http.py", line 1563, in _finishRequestBody
    self.allContentReceived()
  File "/usr/lib/python2.7/dist-packages/twisted/web/http.py", line 1618, in allContentReceived
    req.requestReceived(command, path, version)
  File "/usr/lib/python2.7/dist-packages/twisted/web/http.py", line 773, in requestReceived
    self.process()
--- <exception caught here> ---
  File "/usr/lib/python2.7/dist-packages/twisted/web/server.py", line 132, in process
    self.render(resrc)
  File "/usr/lib/python2.7/dist-packages/twisted/web/server.py", line 167, in render
    body = resrc.render(self)
  File "/usr/lib/python2.7/dist-packages/twisted/web/resource.py", line 216, in render
    return m(request)
  File "/srv/bridges.torproject.org/local/lib/python2.7/site-packages/bridgedb-0.1.5_dirty-py2.7.egg/bridgedb/HTTPServer.py", line 470, in render_POST
    return CaptchaProtectedResource.render_POST(self, request)
  File "/srv/bridges.torproject.org/local/lib/python2.7/site-packages/bridgedb-0.1.5_dirty-py2.7.egg/bridgedb/HTTPServer.py", line 220, in render_POST
    if self.checkSolution(request):
  File "/srv/bridges.torproject.org/local/lib/python2.7/site-packages/bridgedb-0.1.5_dirty-py2.7.egg/bridgedb/HTTPServer.py", line 432, in checkSolution
    if solution.is_valid:
exceptions.AttributeError: Deferred instance has no attribute 'is_valid'

Should be easy, just reorder the current code to make solution.is_valid be checked inside a callback function on the deferred returned from txrecaptcha.submit(). See the test_submit_resultIsRecaptchaResponse() unittest for an example of how it was designed to work.