move key loading to verifier code

Add an option to verifier_test to load keys from a file, the way the
recovery does.

Change-Id: Icba0e391164f2c1a9fefeab4b0bcb878e91d17b4
diff --git a/verifier.h b/verifier.h
index 1bdfca6..e9ef3b7 100644
--- a/verifier.h
+++ b/verifier.h
@@ -24,6 +24,8 @@
 int verify_file(const char* path, const RSAPublicKey *pKeys, unsigned int numKeys);
+RSAPublicKey* load_keys(const char* filename, int* numKeys);
 #define VERIFY_SUCCESS        0
 #define VERIFY_FAILURE        1