Remove the build_ffmpegsumo build variable.

Remove the build_ffmpegsumo build variable.

build_ffmpegsumo no longer serves a purpose, e.g., it's not possible to
build with media_use_ffmpeg=1 and build_ffmpegsumo=0.
This rolls third_party/ffmpeg to pick up the new build files with
build_ffmpegsumo removed.

Committed: https://crrev.com/701cd4b29d05cf564d91ef2a4c536823f691ee73
Cr-Commit-Position: refs/heads/master@{#339320}

[watk, 2015-07-17 17:17:48]

watk@chromium.org changed reviewers:
+ dalecurtis@chromium.org

[watk, 2015-07-17 17:20:12]

watk@chromium.org changed reviewers:
+ jam@chromium.org

[watk, 2015-07-17 17:20:13]

Hi jam@, PTAL at common.gypi

[DaleCurtis, 2015-07-17 18:10:52]

lgtm

[DaleCurtis, 2015-07-17 18:13:29]

dalecurtis@chromium.org changed reviewers:
+ thakis@chromium.org
- jam@chromium.org

[DaleCurtis, 2015-07-17 18:13:29]

-jam, +thakis (build/OWNER)

[Nico, 2015-07-17 20:16:35]

lgtm

[watk, 2015-07-17 20:17:33]

The CQ bit was checked by watk@chromium.org

[commit-bot: I haz the power, 2015-07-17 20:20:15]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1234083004/40001

[commit-bot: I haz the power, 2015-07-17 20:37:41]

Committed patchset #3 (id:40001)

[commit-bot: I haz the power, 2015-07-17 20:38:36]

Patchset 3 (id:??) landed as
https://crrev.com/701cd4b29d05cf564d91ef2a4c536823f691ee73
Cr-Commit-Position: refs/heads/master@{#339320}