devtool: improve parse failure handling

devtool: improve parse failure handling

With the move to tinfoil2, the behaviour when parsing failed has changed
a bit - exceptions are now raised, so handle these appropriately.
Specifically when if parsing the recipe created when running devtool add
fails, rename it to .bb.parsefailed so that the user can run bitbake
afterwards without parsing being interrupted.

Signed-off-by: Paul Eggleton <paul.eggleton@linux.intel.com>