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/tools/blob_interface.hpp b/tools/blob_interface.hpp
index 012550e..7e22849 100644
--- a/tools/blob_interface.hpp
+++ b/tools/blob_interface.hpp
@@ -6,6 +6,9 @@
 #include <string>
 #include <vector>
 
+namespace host_tool
+{
+
 struct StatResponse
 {
     std::uint16_t blob_state;
@@ -45,3 +48,5 @@
         openBlob(const std::string& id,
                  blobs::FirmwareBlobHandler::UpdateFlags handlerFlags) = 0;
 };
+
+} // namespace host_tool