Remove any .gitattributes files within chromium.

These files where inherited from upstream chromium,
but we do not want these as they affect LF/CRLF conversion
by git. And for Qt we require all files using LF endings only.

Change-Id: Ia00881420c4980d4e5f40d9bd132b3c074b3624b
Reviewed-by: Andras Becsi <andras.becsi@theqtcompany.com>