VRT ColorInterp=palette without defining palette causes segfault

[chodgson@…]

A simple .vrt defining a band with a palette color interpretation causes a
segfault when inspected by gdalinfo - it outputs the first part of it's usually
output, then segfaults when it is about to output the palette info. I expect
that this is due to not also defining the palette in the vrt file. Here is the
vrt file I used:

<VRTDataset rasterXSize="512" rasterYSize="512">
 <GeoTransform>0, 0.3515625, 0.0, 0, 0.0, 0.17578125</GeoTransform>
 <VRTRasterBand dataType="Byte" band="1">
  <ColorInterp>palette</ColorInterp>
  <SimpleSource>
   <SourceFilename relativeToVRT="1">test.png</SourceFilename>
   <SourceBand>1</SourceBand>
   <SrcRect xOff="0" yOff="0" xSize="256" ySize="256"/>
   <DstRect xOff="0" yOff="0" xSize="256" ySize="256"/>
  </SimpleSource>
 </VRTRasterBand>
</VRTDataset>

I believe the actual image file "test.png" is unimportant - I've received the
segfault from both .gif and .png files, and changing the colorinterp to "red" in
the vrt allows gdalinfo to work properly.

[warmerdam]

Chris, 

I have fixed gdalinfo to not crash in this situation.