No relative paths for WEB.IMAGEPATH in CGI browse mode

[frank.koormann@…]

It is only partly possible to work with relative path for the WEB.IMAGEPATH in
MapServer 4.0: Maps work, reference, legend and scalebar aren't rendered in 
BROWSE mode. 
The reason seems to be the call of msSaveImage() in
maptemplate.c(msGenerateImages): For the map msObj->Map is handed over as a
parameter of msSaveImage(), for the other three NULL is used. As a consequence
in msSaveImage() the path is expanded using msBuildPath for the map but not for
the others. Not sure if it has some side effects when the call of msSaveIMage is
changed.

[dmorissette]

Um... I don't think there would be any problem in passing the map all the time.
 This looks like legacy code that hasn't been updated properly.

I'll try to cehck this before the 4.2 release.

[dmorissette]

It's been hard to find a way to reproduce this one since only very specific
combinations of relative paths would trigger it.  Anyway, I was able to
reproduce and fix, and confirm that the fix works (in 4.l CVS).