Fix link error when building component build on OS X with OpenSSL.

Fix link error when building component build on OS X with OpenSSL.

Don't build base/keygen_handler_openssl.cc when using
OpenSSL while leaving certificate handling to the OS. Keygen handler
will in these cases be implemented in OS specific code.

BUG=None

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=268808

[haavardm, 2014-05-06 16:05:11]

Ryan: Quick fix for link error mentioned by David in 
https://codereview.chromium.org/263743004/

[Ryan Sleevi, 2014-05-06 18:42:05]

lgtm

[haavardm, 2014-05-06 18:42:52]

The CQ bit was checked by haavardm@opera.com

[commit-bot: I haz the power, 2014-05-06 18:44:40]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/haavardm@opera.com/267133004/1

[commit-bot: I haz the power, 2014-05-07 06:03:59]

FYI, CQ is re-trying this CL (attempt #1).
Please consider checking whether the failures are real,
and report flakes to chrome-troopers@google.com.
The failing builders are:
  win_chromium_compile_dbg on tryserver.chromium

[haavardm, 2014-05-07 07:34:46]

The CQ bit was unchecked by haavardm@opera.com

[haavardm, 2014-05-07 07:34:47]

The CQ bit was checked by haavardm@opera.com

[commit-bot: I haz the power, 2014-05-07 07:38:03]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/haavardm@opera.com/267133004/1

[commit-bot: I haz the power, 2014-05-07 16:28:28]

Change committed as 268808