CommonLibs/Timeval.cpp:61 delta() problem

[wangzhanwei666]

Original:
long Timeval::delta(const Timeval& other) const
{
// 2^31 milliseconds is just over 4 years.
long deltaS = other.sec() - sec();
long deltaUs = other.usec() - usec();
return 1000*deltaS + deltaUs/1000;
}

should Be：
long Timeval::delta(const Timeval& other) const
{
// 2^31 milliseconds is just over 4 years.
long deltaS = (long)other.sec() - (long)sec();
long deltaUs = (long)other.usec() - (long)usec();
return 1000*deltaS + deltaUs/1000;
}

Reason:
usec() return uint32_t type, which will result in (1-2) > 0, deltaUs will be wrong!!!