autocomplete drop_request with multiple requests

shell.py

@@ -220,23 +220,24 @@ class CAManagerShell(cmd.Cmd):
 
             sign_request(self.ca_manager, request_id, authority_id)
 
-    def common_complete_request(self, text, line, begidx, endidx):
-        argc = len(("%send"%line).split())
-        if argc == 2:
-            return [request.req_id for i, request in enumerate(self.ca_manager.request) if request.req_id.startswith(text)]
+    def common_complete_request(self, text, line, begidx, endidx, check_argc=2):
+        argv = ("%send"%line).split()
+        argc = len(argv)
+        if check_argc == None or argc == check_argc:
+            return [request.req_id for i, request in enumerate(self.ca_manager.request) if request.req_id.startswith(text) and request.req_id not in argv[1:]]
 
-    def common_complete_ca(self, text, line, begidx, endidx):
+    def common_complete_ca(self, text, line, begidx, endidx, check_argc=2):
         argc = len(("%send"%line).split())
-        if argc == 2:
+        if check_argc == None or argc == check_argc:
             return [ca_item.ca_id for i, ca_item  in enumerate(self.ca_manager.ca) if ca_item.ca_id.startswith(text)]
 
-    def common_complete_certificate(self, text, line, begidx, endidx):
+    def common_complete_certificate(self, text, line, begidx, endidx, check_argc=2):
         argc = len(("%send"%line).split())
-        if argc == 2:
+        if check_argc == None or argc == check_argc:
             return [certificate.cert_id for i, certificate  in enumerate(self.ca_manager.certificate) if certificate.cert_id.startswith(text)]
 
     def complete_drop_request(self, text, line, begidx, endidx):
-        return self.common_complete_request(text, line, begidx, endidx)
+        return self.common_complete_request(text, line, begidx, endidx, None)
 
     def complete_describe_certificate(self, text, line, begidx, endidx):
         return self.common_complete_certificate(text, line, begidx, endidx)