s4:kdc: fix calculation of the rodc kvno

s4:kdc: fix calculation of the rodc kvno

Bit shifting is non-trivial in C:-)

This

	int32_t a = 0x12340000;
	uint32_t b = (a >> 16);

results in 0x00001234, but this

	int32_t a = 0xEDCB0000;
	uint32_t b = (a >> 16);

results in 0xFFFFEDCB, while we expected 0x0000EDCB.

metze