When trying to build a recipe that uses both git and CMake, the following error message is shown:
CMake Error: The source directory "/home/jorge/cerbero/sources/android_universal/armv7/my-package-1.2" does not appear to contain CMakeLists.txt.

When using CMake:
self.build_dir == ARCH/PACKAGE-VERSION/_builddir (Path where Git extracts sources)
and
self.config_src_dir == ARCH/PACKAGE-VERSION (Path where Git should extract sources)

The problem is that Git class "extracts" sources to self.build_dir.
build_dir is the path to put binaries (as explained in the message of commit 2d520bfd)

Sources have to be extracted to self.config.sources:
- Tarball Class extracts the sources to self.config.sources.
- self.config.sources is also the path where patches are applied.

Part-of: <!700>