tools: put all host-side code into host_tool namespace

To avoid confusion and organize the code itself more cleanly, place the
host-side code into its own namespace.

Change-Id: I573eb0494eb59874adb1d1eadc502499e928e396
Signed-off-by: Patrick Venture <venture@google.com>
diff --git a/test/tools_updater_unittest.cpp b/test/tools_updater_unittest.cpp
index bc7417c..0f49494 100644
--- a/test/tools_updater_unittest.cpp
+++ b/test/tools_updater_unittest.cpp
@@ -6,6 +6,9 @@
 
 #include <gtest/gtest.h>
 
+namespace host_tool
+{
+
 using ::testing::Eq;
 using ::testing::Return;
 using ::testing::StrEq;
@@ -43,3 +46,5 @@
 
     updaterMain(&blobMock, &handlerMock, firmwareImage, signatureFile);
 }
+
+} // namespace host_tool