Initialize all of the fields of the key to zeroes, so that we don't pass
garbage keys in to later versions of Berkeley DB.

Index: b/src/db-XXX.c
===================================================================
--- a/src/db-XXX.c
+++ b/src/db-XXX.c
@@ -223,6 +223,7 @@
   DBT key;								      \
   enum nss_status status;						      \
   const size_t size = (keysize) + 1;					      \
+  memset(&key, 0, sizeof(key));						      \
   key.data = alloca (size);						      \
   key.size = KEYPRINTF keypattern;					      \
   key.flags = 0;							      \