modemmanger-next: backport a upstream patch.

This backports the upstream commit
4e00558fcbdcfc9232f1007e718b9e2afae6520a to fix the error.

BUG=chromium:548901
TEST=the error is gone.

Change-Id: I0b930ad02719ec6f431f7db724979c4264a51b34
Reviewed-on: https://chromium-review.googlesource.com/310656
Commit-Ready: Yunlian Jiang <yunlian@chromium.org>
Tested-by: Yunlian Jiang <yunlian@chromium.org>
Reviewed-by: Prathmesh Prabhu <pprabhu@chromium.org>
1 file changed