metrics-ipmi-blobs: Convert to nanopb

Tested: Decoded a metric proto from a host and verified that the fields
all looked as expected and "normal" with decode successfully identifying
everything.

Change-Id: Iaa1b5500db6d1b93fae95d44a1045a858624cc51
Signed-off-by: William A. Kennington III <wak@google.com>
diff --git a/meson.build b/meson.build
index 100398a..9a1f6e1 100644
--- a/meson.build
+++ b/meson.build
@@ -26,7 +26,9 @@
   ])
 
 # Dummy file to make code coverage happy
-executable('hello', 'hello.c')
+if get_option('tests').allowed()
+  test('hello', executable('hello', 'hello.c'))
+endif
 
 # Meson has no feature option to str...
 tests_str = get_option('tests').allowed() ? 'enabled' : 'disabled'