Migrate from OpenSSL to osmo_get_rand_id()

This avoids potential licensing incompatibility and makes integration of
Debian packaging patches easier.

The libosmocore version requirements are fine already but for jenkins
tests to pass we have to have Ic77866ce65acf524b768882c751a4f9c0635740b
merged into libosmocore master.

Related: OS#1694
Change-Id: I2b687b7f07ef05bbd861b8479cad5a958a3dde92
8 files changed