Bug 988

The projection label can show incorrect labels (i.e. it doesn't find a match in
the projection shared resource.  Since this code has been used, unchanged, for a
couple of years, it seems that something may have changed in mapscript's
reporting of the projection string.

Changing the index at which the code looks for the epsg code from 5 to 6 makes
it work.  Inspecting the projection, it seems that the projection is now
reported with a "+" in front of it.  This only happens if you call
'setProjection' on the map object (i.e. if you have a projection defined without
the + then it works until you change projections).

The code for detecting the epsg code is not very robust and needs to be updated
to search for epsg:xxxxx rather than use a fixed offset in a string.