Remove re-check of hash algorithm since it's checked in initialize

Author: vcsjones

lib/ssh_data/signature.rb

@@ -85,8 +85,6 @@ def verify(signed_data)
         end
       end
 
-      raise AlgorithmError, "Unsupported digest algorithm #{@hash_algorithm}" if digest_algorithm.nil?
-
       message_digest = digest_algorithm.digest(signed_data)
       blob =
         SIGNATURE_PREAMBLE +