bitbake: siggen: handle recipe path changes in siginfo files

bitbake: siggen: handle recipe path changes in siginfo files

Avoid storing paths to files in SRC_URI when writing out the the
file checksums to siginfo files. This prevents a move of the source
directory being reported by bitbake-diffsigs as files being removed and
then added (the signature itself is not affected since the file paths
have never been included in the signature).

This has required the format of the file checksums in the siginfo file
to be changed from a dict to a list of tuples (in order to handle
multiple files with the same name under different paths, which is
uncommon but possible); the code remains backwards-compatible with older
siginfo files that use a dict however.

Fixes [YOCTO #5245].

(Bitbake rev: e4d3077c5b0cc57964640512f3646c2d73c1d855)

Signed-off-by: Paul Eggleton <paul.eggleton@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>