bitbake/fetcher: Deal with a ton of different bugs
The more we try and patch up the fetcher code, the more things break. The
code blocks in question are practically unreadable and are full of corner
cases where fetching could fail. In summary the issues noticed included:
a) Always fetching strange broken urls from the premirror for "noclone"
git repositories
b) Not creating or rewriting .md5 stamp files inconsistently
c) Always fetching git source mirror tarballs from the premirror even
if they already exist but the checkout directory does now
d) Passing "None" values to os.access() and os.path.extsts() checks under
certain circumstances
e) Not using fetched git mirror tarballs if the preexist and always
try and fetch them.
This patch rewrites the sections of code in question to be simpler and
more readable, fixing the above problems and most likely other odd
corner cases.
Signed-off-by: Richard Purdie <rpurdie@linux.intel.com>
