Make the default alternate protcol probability threshold 1, not 0.

Make the default alternate protcol probability threshold 1, not 0.
This means that by default, Chrome will honor headers like:
  Alternate-Protocol: 80:quic
  Alternate-Protocol: 80:quic,p=1
But not:
  Alternate-Protocol: 80:quic,p=.5
Eventually we need to switch to a dynamic threshold, but on step at a time.

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=285473

[ramant (doing other things), 2014-07-24 17:25:12]

lgtm

[Ryan Hamilton, 2014-07-24 17:26:29]

The CQ bit was checked by rch@chromium.org

[commit-bot: I haz the power, 2014-07-24 17:27:47]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/rch@chromium.org/411423003/1

[commit-bot: I haz the power, 2014-07-24 20:38:18]

FYI, CQ is re-trying this CL (attempt #1).
The failing builders are:
  linux_chromium_chromeos_rel on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/linux_chromium_chrome...)
  linux_chromium_rel_swarming on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/linux_chromium_rel_sw...)
  win_chromium_rel on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/win_chromium_rel/buil...)

[commit-bot: I haz the power, 2014-07-24 21:13:03]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2014-07-24 21:13:03]

Try jobs failed on following builders:
  linux_chromium_rel_swarming on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/linux_chromium_rel_sw...)

[Ryan Hamilton, 2014-07-25 01:57:35]

The CQ bit was checked by rch@chromium.org

[commit-bot: I haz the power, 2014-07-25 02:25:55]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/rch@chromium.org/411423003/1

[commit-bot: I haz the power, 2014-07-25 03:57:01]

Change committed as 285473