I missed generate_signing_key

Author: David Robertson

setup.py

@@ -159,6 +159,7 @@ def exec_file(path_segments):
             "export_signing_key = synapse._scripts.export_signing_key:main",
             "generate_config = synapse._scripts.generate_config:main",
             "generate_log_config = synapse._scripts.generate_log_config:main",
+            "generate_signing_key = synapse._scripts.generate_signing_key:main",
             "hash_password = synapse._scripts.hash_password:main",
             "register_new_matrix_user = synapse._scripts.register_new_matrix_user:main",
             "synapse_port_db = synapse._scripts.synapse_port_db:main",