Revert of Run pkg-config for Udev only if use_udev==1

Revert of Run pkg-config for Udev only if use_udev==1 (patchset #1 of https://codereview.chromium.org/429723002/)

Reason for revert:
Breaks builds where use_udev==0 since certain targets just assume udev and never check against use_udev.

Udev package should be wrapped in a use_udev confitional altogether and all the locations using Udev should check against use_udev.

Original issue's description:
> Run pkg-config for Udev only if use_udev==1
> 
> Some embedded platforms do not have udev support. The change will skip
> running pkg-config if use_udev=0.
> 
> BUG=none
> 
> Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=288770

TBR=brettw@chromium.org
NOTRY=true

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=289280

[dnicoara, 2014-08-13 13:44:03]

Created Revert of Run pkg-config for Udev only if use_udev==1

[commit-bot: I haz the power, 2014-08-13 13:45:24]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/dnicoara@chromium.org/469763002/1

[commit-bot: I haz the power, 2014-08-13 13:45:25]

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

[commit-bot: I haz the power, 2014-08-13 13:45:26]

No LGTM from a valid reviewer yet. Only full committers are accepted.
Even if an LGTM may have been provided, it was from a non-committer or
a provisional committer, _not_ a full super star committer.
See http://www.chromium.org/getting-involved/become-a-committer
Note that this has nothing to do with OWNERS files.

[dnicoara, 2014-08-13 13:48:41]

The CQ bit was checked by dnicoara@chromium.org

[commit-bot: I haz the power, 2014-08-13 13:49:13]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/dnicoara@chromium.org/469763002/1

[commit-bot: I haz the power, 2014-08-13 13:50:23]

Committed patchset #1 (1) as 289280