Return value of snprintf can be more than size value when output
is truncated, so copying the '\0' at return value may cause array
index out-of-bound access. And as snprintf function takes care of
terminating the string with '\0', its redundant to copy '\0' at
return value.
CRs-Fixed: 947966
Change-Id: Ic5dab6d9aa57db5000f23c82e2a22924e0154c40