Update bootstrap handling to ensure key and fsid are present before

trying to init and start OSD devices.

Refactor osd device rescanning into ceph package.

hooks/ceph.py

@@ -72,9 +72,22 @@ def is_osd_disk(dev):
         pass
     return False
 
+
+def rescan_osd_devices():
+    cmd = [
+        'udevadm', 'trigger',
+        '--subsystem-match=block', '--action=add'
+        ]
+
+    subprocess.call(cmd)
+
 _bootstrap_keyring = "/var/lib/ceph/bootstrap-osd/ceph.keyring"
 
 
+def is_bootstrapped():
+    return os.path.exists(_bootstrap_keyring)
+
+
 def import_osd_bootstrap_key(key):
     if not os.path.exists(_bootstrap_keyring):
         cmd = [