linux-yocto/3.8: revert .gitignore: do not ignore meta directory

linux-yocto/3.8: revert .gitignore: do not ignore meta directory

We made a change to allow meta branch/directory changes to be visible
when working with the kernel tree. But without associated tool changes
.gitignore is different between branches and hence causes errors when
changing branches and processing the tree.

The tools changes are not ready yet, so to avoid patching issues,
temporarily reverting the change.

(From OE-Core rev: f7e66abf279781d7c0cc1fb3c32c93c15a83c52c)

Signed-off-by: Bruce Ashfield <bruce.ashfield@windriver.com>
Signed-off-by: Saul Wold <sgw@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>