[GN] Remove cflags_c from objc and cflags_cc from objcxx toolchains

[GN] Remove cflags_c from objc and cflags_cc from objcxx toolchains

//build/config/compiler/BUILD.gn has the following lines which make the declarations in the toolchains superfluous:

  # Pass the same C/C++ flags to the objective C/C++ compiler.
  cflags_objc += cflags_c
  cflags_objcc += cflags_cc

R=brettw@chromium.org
BUG=none

Committed: https://crrev.com/bd1aafe5d735405a27266a38a0af38be2d17d0bd
Cr-Commit-Position: refs/heads/master@{#348197}

[brettw, 2015-09-10 17:36:06]

lgtm

[Bons, 2015-09-10 17:43:18]

The CQ bit was checked by andybons@chromium.org

[commit-bot: I haz the power, 2015-09-10 17:44:18]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1335503006/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1335503006/1

[commit-bot: I haz the power, 2015-09-10 18:30:43]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-09-10 18:34:52]

Patchset 1 (id:??) landed as
https://crrev.com/bd1aafe5d735405a27266a38a0af38be2d17d0bd
Cr-Commit-Position: refs/heads/master@{#348197}

[commit-bot: I haz the power, 2015-09-23 12:12:32]

Patchset 1 (id:??) landed as
https://crrev.com/bd1aafe5d735405a27266a38a0af38be2d17d0bd
Cr-Commit-Position: refs/heads/master@{#348197}