lib/gssapi/ntlm: _gss_ntlm_allocate_ctx handle calloc failure

If a memory allocation failure occurs, return an error instead of
triggering a segmentation fault.

Change-Id: I38f5e88ca2f1ba7411b05a35b925168015261eb4

lib/gssapi/ntlm/accept_sec_context.c

@@ -50,6 +50,10 @@ _gss_ntlm_allocate_ctx(OM_uint32 *minor_status, ntlm_ctx *ctx)
 	return GSS_S_FAILURE;
 
     *ctx = calloc(1, sizeof(**ctx));
+    if (*ctx == NULL) {
+	*minor_status = ENOMEM;
+	return GSS_S_FAILURE;
+    }
 
     (*ctx)->server = ns_interface;