utils/ssh: Try to free up resources during client creation

SshConnection._make_client() may throw exceptions for several reasons
(e.g., target is not ready yet). The client should be closed if that is
the case. Otherwise Python unittest like tools report resource warning
for 'unclosed socket', etc.

Signed-off-by: Douglas Raillard <douglas.raillard@arm.com>
Signed-off-by: Metin Kaya <metin.kaya@arm.com>

devlib/utils/ssh.py

@@ -367,6 +367,8 @@ class SshConnection(SshConnectionBase):
         else:
             logger.debug('Using SFTP for file transfer')
 
+        self.client = None
+        try:
             self.client = self._make_client()
             atexit.register(self.close)
 
@@ -387,6 +389,11 @@ class SshConnection(SshConnectionBase):
                 )
             )
 
+        except BaseException:
+            if self.client is not None:
+                self.client.close()
+            raise
+
     def _make_client(self):
         if self.strict_host_check:
             policy = RejectPolicy