[GN]: Fix bug where cflag vars were not being written on non-PCH builds

[GN]: Fix bug where cflag vars were not being written on non-PCH builds

On non-PCH builds, the cflags* vars were not being properly written in
the binary output.

Also removed some dead vars.

BUG=535040
Committed: https://crrev.com/4f28b8c3f0895976d060159edd5271c8a6a2a92a
Cr-Commit-Position: refs/heads/master@{#350294}

[Bons, 2015-09-23 01:57:24]

andybons@chromium.org changed reviewers:
+ brettw@chromium.org, dpranke@chromium.org

[brettw, 2015-09-23 03:12:12]

The CQ bit was checked by brettw@chromium.org

[brettw, 2015-09-23 03:12:12]

lgtm

[commit-bot: I haz the power, 2015-09-23 03:13:50]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1359243002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1359243002/1

[commit-bot: I haz the power, 2015-09-23 03:55:21]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-09-23 03:55:58]

Patchset 1 (id:??) landed as
https://crrev.com/4f28b8c3f0895976d060159edd5271c8a6a2a92a
Cr-Commit-Position: refs/heads/master@{#350294}