WFS 1.1.0 GetCapabilities crashes MapServer 6.2

[taroy1]

Having rebuilt MapServer today with the latest code from the 6.2 branch, performing a WFS version 1.1.0 GetCapabilities request now crashes MapServer. A WFS version 1.0.0 request works fine.

Here is an example WFS request with map file that results in the crash:

http://localhost/cgi-bin/mapserv.exe?map=C:\tmp\test.map&SERVICE=WFS&REQUEST=GetCapabilities&VERSION=1.1.0

MAP
 NAME "Test"
 
 WEB
   METADATA
     ows_enable_request "*"
   END
 END

 PROJECTION
   "init=epsg:4326"
 END

 LAYER
   NAME "GreenBox"
   TYPE POLYGON
   FEATURE
     WKT "POLYGON ((0 0,6 0,6 6,0 6,0 0))"
   END
   CLASS
     STYLE
       COLOR 0 255 0
     END
   END
 END

END

[tbonfort]

cc @faegi . This was brought in by 9bcec4f :

/* add namespace to layer name */
  value = msOWSLookupMetadata(&(map->web.metadata), "FO", "namespace_prefix");
  n = strlen(value)+strlen(lp->name)+1+1;

value must be checked for NULL (the whole block probably needs checking: what namespace to use if none was supplied?)