The added error checking on plugin initialization in
commit 9f8eb1d9ca0f56d6292db5858c52e6873d0abe51 broke the ability of
loading plugins by their basename from default linker locations.
Only use stat() for directory discovery and leave error handling
to dlopen() to restore former behavior.
Fixes: 9f8eb1d9ca0f ("eal: support driver loading from directory")
Signed-off-by: Panu Matilainen <pmatilai@redhat.com>