package.bbclass: Improve shlibs provider code

:Release Notes:
All changes will be probably included in oe-core 1.6, but because we
have many prebuilt binaries, we need those changes sooner.

:Detailed Notes:
Most changes are included in
http://git.openembedded.org/openembedded-core-contrib/log/?h=jansa/shlib-providers

:Testing Performed:
Only build tested.

:Build Notes:
Invalidates all sstate signatures.

:QA Notes:
No change to image.

:Issues Addressed:
[GF-52616] Improve shlibs code

Open-webOS-DCO-1.0-Signed-off-by: Martin Jansa <martin.jansa@lge.com>

Change-Id: I2de5b40eaba029a52decb6fc16e2fa1faad1f1be
Reviewed-on: https://g2g.palm.com/3909
Reviewed-by: DCO Verification
Reviewed-by: Martin Jansa <Martin.Jansa@lge.com>
Tested-by: Martin Jansa <Martin.Jansa@lge.com>
Reviewed-by: Susan Montooth <susan.montooth@lge.com>