Remove --enable-spdy4 and --enable-npn-http command line flags.

Remove --enable-spdy4 and --enable-npn-http command line flags.

Remove --enable-spdy4 and --enable-npn-http command line flags that used to
force enable and disable both of HTTP/2 and SPDY/3.1, respectively.  They are
obsolete because
 * these protocols are not experimental any more,
 * they are enabled by default,
 * usage of disabling flag is very low and it is unlikely that these flags will
   ever be needed for debugging.

BUG=

Committed: https://crrev.com/f7ed9b85d9b6ed0d0dfa80d9838890200c399c07
Cr-Commit-Position: refs/heads/master@{#329407}

[Bence, 2015-05-12 14:13:58]

bnc@chromium.org changed reviewers:
+ rch@chromium.org

[Bence, 2015-05-12 14:13:58]

Ryan, PTAL.  Thanks.

[Ryan Hamilton, 2015-05-12 14:16:00]

lgtm

[Bence, 2015-05-12 14:19:19]

The CQ bit was checked by bnc@chromium.org

[commit-bot: I haz the power, 2015-05-12 14:19:26]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1130353003/1

[commit-bot: I haz the power, 2015-05-12 15:04:21]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-05-12 15:04:58]

Patchset 1 (id:??) landed as
https://crrev.com/f7ed9b85d9b6ed0d0dfa80d9838890200c399c07
Cr-Commit-Position: refs/heads/master@{#329407}