Always wait for the cmd to finish (#14006)

After cancelling the context we still need to wait for the
command to finish otherwise zombie processes may occur

Fix #13987

Signed-off-by: Andrew Thornton <art27@cantab.net>

Co-authored-by: 6543 <6543@obermui.de>

modules/git/command.go

@@ -153,6 +153,7 @@ func (c *Command) RunInDirTimeoutEnvFullPipelineFunc(env []string, timeout time.
 		err := fn(ctx, cancel)
 		if err != nil {
 			cancel()
+			_ = cmd.Wait()
 			return err
 		}
 	}