Remove cgpt app-specific symbols from libvboot_host.a

Three symbols used by the standalone cgpt executable were being referenced
in the files used to create the external libvboot_host.a needed by non-vboot
userspace applications.

This cleans things up so those symbols don't have to be explictly defined
by other repos just to link with that library.

BUG=chromium:318536
BRANCH=ToT
TEST=manual

No new functionality, just code cleanup. Tested with

  make runtests runfutiltests runlongtests

Change-Id: Ibc77fb9800c89d7109ebf38d4d6729f52665722f
Signed-off-by: Bill Richardson <wfrichar@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/205667
Reviewed-by: Randall Spangler <rspangler@chromium.org>
diff --git a/cgpt/cgpt.c b/cgpt/cgpt.c
index e49d430..ccf7318 100644
--- a/cgpt/cgpt.c
+++ b/cgpt/cgpt.c
@@ -15,8 +15,13 @@
 #include "vboot_host.h"
 
 const char* progname;
-const char* command;
-void (*uuid_generator)(uint8_t* buffer);
+
+int GenerateGuid(Guid *newguid)
+{
+  /* From libuuid */
+  uuid_generate(newguid->u.raw);
+  return CGPT_OK;
+}
 
 struct {
   const char *name;
@@ -90,8 +95,7 @@
   int i;
   int match_count = 0;
   int match_index = 0;
-
-  uuid_generator = uuid_generate;
+  char* command;
 
   progname = strrchr(argv[0], '/');
   if (progname)