bug#20874: Split -d skips to 9000 at 90

[Kevin Tan]

Coreutils version: 8.23-3ubuntu1
Operating system: Ubuntu 15.04

Split with numeric suffixes adds extra digits in the suffix from 90+ and begins counting again from the 9000s. All 90s after the first have no jumps.

Example:
    split -b 2048 -d testfile.bin splitfile.

With a large enough test file (721KB) the resultant files:
splitfile.00, splitfile01, splitfile.02
...
splitfile.89, splitfile.9000, splitfile.9001, splitfile.9002
...
splitfile.9262, etc.