selinux: treat empty seclabel as non-existant
selinux: treat empty seclabel as non-existant

Empty seclabels are non-existant. Make sure we skip them in
GetConnectionCredentials().

Signed-off-by: David Herrmann <fb53b2ddb8d141e0cb39d7c67c2f81b6bc2eb0f7@gmail.com>

bus1/dbus-broker