Implement detach media

Allow detaching remote media, the converse of the attach_media call

Change-Id: I45c71e02bb817b5c26b4de87b52de90c273ce526

pyghmi/ipmi/command.py

@@ -1726,3 +1726,7 @@ class Command(object):
         """
         self.oem_init()
         self._oem.attach_remote_media(url, username, password)
+
+    def detach_remote_media(self):
+        self.oem_init()
+        self._oem.detach_remote_media()

pyghmi/ipmi/oem/generic.py

@@ -224,5 +224,8 @@ class OEMHandler(object):
         """
         return
 
+    def detach_remote_media(self):
+        raise exc.UnsupportedFunctionality()
+
     def attach_remote_media(self, imagename, username, password):
         raise exc.UnsupportedFunctionality()

pyghmi/ipmi/oem/lenovo/handler.py

@@ -676,3 +676,9 @@ class OEMHandler(generic.OEMHandler):
                                                imagename, domain, path, host)
                 else:
                     raise
+
+    def detach_remote_media(self):
+        if self.has_megarac:
+            self.ipmicmd.xraw_command(
+                netfn=0x32, command=0x9f, data=(8, 10, 0, 0))
+            self.ipmicmd.xraw_command(netfn=0x32, command=0x9f, data=(8, 11))