Add support for non-santized kernel provides

This fixed some issues on building on plain openembedded instead of Yocto.
More info on this topic:

http://lists.openembedded.org/pipermail/openembedded-core/2012-July/064044.html

If the kernel version string uses characters or symbols that
need to be santized for the package name, we can end up with a
mismatch between module requirements and what the kernel
provides.

The kernel version is pulled from utsrelease.h, which contains
the exact string that was passed to the kernel build, not
one that is santized, this can result in:

 echo "CONFIG_LOCALVERSION="\"MYVER+snapshot_standard\" >> ${B}/.config

 <build>

 % rpm -qp kernel-module-uvesafb-3.4-r0.qemux86.rpm --requires
update-modules
kernel-3.4.3-MYVER+snapshot_standard
 % rpm -qp kernel-3.4.3-myver+snapshot-standard-3.4-r0.qemux86.rpm --provides
kernel-3.4.3-myver+snapshot-standard = 3.4-r0

At rootfs assembly time, we'll have a dependency issue with the kernel
providing the santizied string and the modules requiring the utsrelease.h
string.

To not break existing use cases, we can add a second provides to the
kernel packaging with the unsantized version string, and allowing the
kernel module packaging to be unchanged.

   RPROVIDES_kernel-base += "kernel-${KERNEL_VERSION}"

 % rpm -qp kernel-3.4.3-myver+snapshot-standard-3.4-r0.qemux86.rpm --provides
kernel-3.4.3-MYVER+snapshot_standard
kernel-3.4.3-myver+snapshot-standard = 3.4-r0

Signed-off-by: Christian Ege <k4230r6@gmail.com>