Rename Bluetooth OBEX dissector to OBEX

Rename Bluetooth OBEX dissector to OBEX

For historiacal reasons OBEX protocol was implemented as
"Bluetooth OBEX", that means it is OBEX + Bluetooth related stuff.
However Bluetooth related stuff does not caused any issue right now,
so allow to use this dissector in non-Bluetooth cases.

Bug: 11724
Change-Id: Ic645308bc854602d009f254ebbfd1b703a4c6a25
Reviewed-on: https://code.wireshark.org/review/13740
Petri-Dish: Michal Labedzki <michal.labedzki@tieto.com>
Tested-by: Petri Dish Buildbot <buildbot-no-reply@wireshark.org>
Reviewed-by: Pascal Quantin <pascal.quantin@gmail.com>
Reviewed-by: Anders Broman <a.broman58@gmail.com>