If patches fail to apply with git, quilt it used as a fallback. If that
happens, the code in this class is meant to handle cleanup of these patch
files. In the case where ${S} is a subdir of the git tree, the code doesn't
correctly set the patches directory.
This change correctly sets the patches directory (which is different to the
location of the git repository).
[YOCTO #7911]
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
