lib/devtool/standard: Fix patch cleanup
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]
(From OE-Core master rev:
de6e0f3af5e858960676ea291036e59105fd806f)
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
Signed-off-by: Joshua Lock <joshua.lock@collabora.co.uk>
