warnings go to stdout, not stderr

[lunarpapillo]

The WARNING line was issued to stdout. I'd expect it to go to stderr.

$ /home/papillo/work/LunarG/gfxreconstruct/build/tools/compress/gfxrecon-compress /tmp/resvi/dota2/compress-native-to-LZ4-results/dota2-LZ4.gfxr /tmp/resvi/dota2/compress-LZ4-to-ZLIB-results/dota2-ZLIB.gfxr ZLIB
[gfxrecon] WARNING - Skipping unrecognized file block with type 0
Compression Results:
  Original Size   [Compression:   LZ4] = 304942678324 bytes
  Compressed Size [Compression:  ZLIB] = 259 bytes
  Percent Reduction                    = 100.00%$