lib/oe/recipeutils: fix invalid character detection in validate_pn()
* validate_pn() is supposed to protect against invalid characters, fix
the function so that it actually does (unanchored regex strikes
again...)
* However, now that the function is enforcing the restrictions, we do
still want to allow + in recipe names (e.g. "gtk+")
Signed-off-by: Paul Eggleton <paul.eggleton@linux.intel.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
