DELTA encoding may exaggerate number of bits required

Consider the following code:

    this.min = literals[0];
    long max = literals[0];
    final long initialDelta = literals[1] - literals[0];
    long currDelta = initialDelta;
    long deltaMax = initialDelta;
    this.adjDeltas[0] = initialDelta;

Given the following sequence of longs:

deltaMax would be 10000. deltaMax is used to determine the bit width of the encoded delta array, but the bit-packed output doesn't include the first delta--rather, it's encoded in Delta Base as a varint.

I believe deltaMax should be set to 0 initially, allowing the later check for (i > 1) to ignore the first delta correctly.

Sorry for no pull request with a regression test case. I'm not set up for java development here. It may also be that I'm reading this wrong.