Run os.kill for all child pids even after some of them are down

Right now, we come out of the iteration in case of failure while trying to kill a child pid. This may result in some of the child pids staying alive. Change-Id: I18d58fcefec2bbdae4ae9bf73594939ade241b52

Author: OswinNathanial

git/cmd.py

@@ -618,7 +618,10 @@ def _kill_process(pid):
 try:
 os.kill(pid, SIGKILL)
 forchild_pidinchild_pids:
-os.kill(child_pid, SIGKILL)
+try:
+os.kill(child_pid, SIGKILL)
+exceptOSError:
+pass
 kill_check.set() # tell the main routine that the process was killed
 exceptOSError:
 # It is possible that the process gets completed in the duration after timeout