avoid uninit variable and unreachable code warnings

most of these warnings are not problems because of ample
use of abort() calls.  However, the large number of warnings
makes it difficult to identify real problems.  Initialize
the variables to shut up the compilers.

Change-Id: I8477c11b17c7b6a7d9074c721fdd2d7303b186a8

lib/gssapi/krb5/init_sec_context.c

@@ -529,7 +529,7 @@ init_auth_restart
     Checksum cksum;
     krb5_enctype enctype;
     krb5_data fwd_data, timedata;
-    int32_t offset = 0, oldoffset;
+    int32_t offset = 0, oldoffset = 0;
     uint32_t flagmask;
 
     krb5_data_zero(&outbuf);