ui/vnc: simplify and avoid strncpy

Don't bother with strncpy.  There's no need for its zero-fill.
Use g_strndup in place of g_malloc+strncpy+NUL-terminate.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Jim Meyering <meyering@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
diff --git a/ui/vnc-auth-sasl.c b/ui/vnc-auth-sasl.c
index 8fba770..bfdcb46 100644
--- a/ui/vnc-auth-sasl.c
+++ b/ui/vnc-auth-sasl.c
@@ -432,9 +432,7 @@
 
 static int protocol_client_auth_sasl_mechname(VncState *vs, uint8_t *data, size_t len)
 {
-    char *mechname = g_malloc(len + 1);
-    strncpy(mechname, (char*)data, len);
-    mechname[len] = '\0';
+    char *mechname = g_strndup((const char *) data, len);
     VNC_DEBUG("Got client mechname '%s' check against '%s'\n",
               mechname, vs->sasl.mechlist);