It's possible for new version of ofono or connman to want to use bluez5, via the PACKAGECONFIG settings, we need to allow that to happen without having to embed bluez4 vs bluez5 in the recipe.
This can be done with a virtual/bluez style of declaration. Examples of this can be seen for virtual/libc and in the meta/conf/distro/include/default-providers.inc file.
From what I see, this can not be done using PACKAGECONFIG without breaking some things. The only clean way is the solution proposed by Cristian with a virtual/bluez style that should be used by all packages, but the problem is that not all packages have support for bluez5. This should be postponed until there is more support for bluez5.
Pushed back due to task prioritization.
Investigation started.
Fixed with commit: http://git.yoctoproject.org/cgit/cgit.cgi/poky/commit/?id=3f8c532e6d478afcae15580bfe3ec33f89319d50