platform2: Explicitly use base:: namespace with CommandLine

The current revision of libchrome is removing CommandLine class
from global namespace and only retain the one in base::.

Sweep the code to use the correct namespace in anticpation of
libchrome revision roll.

BUG=None
TEST=./build_packages

Change-Id: Ib7ca448dac1204c1e36ab053e775a5a5214997ac
Reviewed-on: https://chromium-review.googlesource.com/263785
Trybot-Ready: Alex Vakulenko <avakulenko@chromium.org>
Tested-by: Alex Vakulenko <avakulenko@chromium.org>
Reviewed-by: Alex Deymo <deymo@chromium.org>
Commit-Queue: Alex Vakulenko <avakulenko@chromium.org>
diff --git a/buffet/test_daemon/main.cc b/buffet/test_daemon/main.cc
index 4afc35d..65372fb 100644
--- a/buffet/test_daemon/main.cc
+++ b/buffet/test_daemon/main.cc
@@ -109,7 +109,7 @@
 }
 
 int main(int argc, char* argv[]) {
-  CommandLine::Init(argc, argv);
+  base::CommandLine::Init(argc, argv);
   chromeos::InitLog(chromeos::kLogToSyslog |
                     chromeos::kLogToStderr |
                     chromeos::kLogHeader);