Correctly report failure to swap RELRO pages.

Correctly report failure to swap RELRO pages.

If no RELRO pages are swapped, the library reports an error by
returning false, but currently does not supply any message for the
log.  Add one.

BUG=

Committed: https://crrev.com/306811ea503c4a00f2e565ddd543134c44e3a2a1
Cr-Commit-Position: refs/heads/master@{#300120}

[simonb (inactive), 2014-10-17 16:29:27]

simonb@chromium.org changed reviewers:
+ rmcilroy@chromium.org

[rmcilroy, 2014-10-17 16:37:43]

On 2014/10/17 16:29:28, simonb wrote:

lgtm, thanks!

[simonb (inactive), 2014-10-17 16:39:23]

The CQ bit was checked by simonb@chromium.org

[commit-bot: I haz the power, 2014-10-17 16:39:36]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/649183006/1

[commit-bot: I haz the power, 2014-10-17 17:02:43]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2014-10-17 17:03:34]

Patchset 1 (id:??) landed as
https://crrev.com/306811ea503c4a00f2e565ddd543134c44e3a2a1
Cr-Commit-Position: refs/heads/master@{#300120}