ceph-volume: Fix unbound var in disk.get_devices()

00ba00f looks to have regressed.

Signed-off-by: Zack Cerza <[email protected]>

Author: zmc

src/ceph-volume/ceph_volume/util/disk.py

@@ -878,6 +878,7 @@ def get_devices(_sys_block_path='/sys/block', device=''):
         for key, file_ in facts:
             metadata[key] = get_file_contents(os.path.join(sysdir, file_))
 
+        device_slaves = []
         if block[2] != 'part':
             device_slaves = os.listdir(os.path.join(sysdir, 'slaves'))
             metadata['partitions'] = get_partitions_facts(sysdir)