devtool: update-recipe: support replacing remote patches

devtool: update-recipe: support replacing remote patches

If you have a patch remotely fetched in a recipe (e.g. from an http
server) that needs updating then add a local version and substitute the
entry in SRC_URI to point to it.

One can argue about how desirable it is to be modifying patches fetched
in this way, but then one can argue about how desirable it is to have
such patches in the recipe in the first place - and in any case if
devtool update-recipe is to correctly transfer changes to such patches
made in the git repository within the source tree to the recipe then
there isn't much choice but to do it this way.

(From OE-Core rev: a19c26cc78a181f9dd2706dd42e7e450d7ad4082)

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