Fix check_seapp segfault and undefined linking err

When LINK_SEPOL_STATIC was not defined, symbol
log_warning was trying to be resolved by the linker.
That symbol was not defined as it should have been
log_warn and not log_warning.

When a key would be validated in key_map_validate(), an
unchecked key, like user, could cuase a segfault when
the se_key was getting free'd no matter what at the end
of the function, even if no se_key was alloc'd.

Change-Id: If334ba7350e6d2ad1fa9bed142bb2fabe7caa057