This change correctly handles devices with underscores in their
name even if there is a device with the same name after the last
underscore (spyder, umts_spyder) by not allowing any underscores
in the manufacturers name.
Without this change, spyder gets resolved to:
device/motorola_umts/spyder
device/motorola/spyder
Only the last one is valid.
With this change, both spyder and umts_spyder get resolved correctly.
Change-Id: I0c95ff126d827a2d6b58875dfcb9327e999f4913
29f3b5775b