log: remove deprecated functions

Remove rte_set_log_level(), rte_get_log_level(),
rte_set_log_type(), and rte_get_log_type().

Also update librte_eal.so version in docuementation.
The LIBABIVER variable in eal has already been modified in
commit f26ab687a74f ("eal: remove Xen dom0 support").

Signed-off-by: Olivier Matz <olivier.matz@6wind.com>