Move errors from import to connect (#50034) (#50036)

* Move errors from import to connect (#50034)

(cherry picked from commit bf4ad56479)

* Add changelog fragment.

changelogs/fragments/50034-move-import-errors.yaml

@@ -0,0 +1,3 @@
+---
+bugfixes:
+- Moved error in netconf connection plugin from at import to on connection.

lib/ansible/plugins/connection/netconf.py

@@ -187,8 +187,9 @@ try:
     from ncclient.operations import RPCError
     from ncclient.transport.errors import SSHUnknownHostError
     from ncclient.xml_ import to_ele, to_xml
+    HAS_NCCLIENT = True
 except ImportError:
-    raise AnsibleError("ncclient is not installed")
+    HAS_NCCLIENT = False
 
 try:
     from __main__ import display
@@ -245,8 +246,13 @@ class Connection(NetworkConnectionBase):
             return super(Connection, self).exec_command(cmd, in_data, sudoable)
 
     def _connect(self):
-        super(Connection, self)._connect()
+        if not HAS_NCCLIENT:
+            raise AnsibleError(
+                'ncclient is required to use the netconf connection type.\n'
+                'Please run pip install ncclient'
+            )
 
+        super(Connection, self)._connect()
         display.display('ssh connection done, starting ncclient', log_only=True)
 
         allow_agent = True