Fix variable typos in rfrecv related methods.

lib/msf/core/post/hardware/rftransceiver/rftransceiver.rb

@@ -135,6 +135,7 @@ module RFTransceiver
   def rfrecv(timeout = -1, blocksize = -1)
     return "" if not is_rf?
     self.index ||= 0
+    opts = {}
     opts["timeout"] = timeout if not timeout == -1
     opts["blocksize"] = blocksize if not blocksize == -1
     client.rftransceiver.rfrecv(self.index, opts)

lib/rex/post/hwbridge/extensions/rftransceiver/rftransceiver.rb

@@ -106,7 +106,7 @@ class RFTransceiver < Extension
       end
       if opt.has_key? "blocksize"
         request += "&" if not first
-        request += "blocksize=#{blocksize}"
+        request += "blocksize=#{opt['blocksize']}"
       end
     end
     data = client.send_request(request)