oe-selftest: devtool: add some tests for devtool add -f
Tests the following aspects of "devtool add" with the -f option:
* Works for a git and https URI
* Extracts to the appropriate directory
* Uses the correct recipe file name with and without -V
* Sets SRC_URI and S appropriately with and without -V
* Sets SRCREV if rev= is specified in the URI
A lot of this functionality relies on "recipetool create" which
"devtool add" wraps around, so the associated behaviour of that is also
being tested here.
Refactor out the code to check a recipe for variable values / inherits
at the same time so we can use it to check the generated recipe.
Signed-off-by: Paul Eggleton <paul.eggleton@linux.intel.com>
