Add a note about false positives on "copyright" word into licenses checker

Add a note about false positives on "copyright" word into licenses checker

It is required to scan the entire file for potential copyright references,
as third-party code may appear anywhere in the file, so false positives
are unfortunately inevitable for comments containing the "C-word".

Add a note to the scanner message to provide a hint on that.

BUG=243570
TBR=torne@chromium.org

Committed: https://crrev.com/6508758837638553b83bcef6602e9b6bb9e52e95
Cr-Commit-Position: refs/heads/master@{#333124}

[mnaganov (inactive), 2015-06-05 20:29:50]

TBR'ing as it's only a change in the text of messages.

[mnaganov (inactive), 2015-06-05 20:29:56]

The CQ bit was checked by mnaganov@chromium.org

[commit-bot: I haz the power, 2015-06-05 20:30:33]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1161943005/1

[commit-bot: I haz the power, 2015-06-05 20:48:10]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-06-05 20:49:02]

Patchset 1 (id:??) landed as
https://crrev.com/6508758837638553b83bcef6602e9b6bb9e52e95
Cr-Commit-Position: refs/heads/master@{#333124}