Compilation error on Linux

```
When compiling the current git master, I got the following error with gcc 4.6.1:

src/XercesExtensions/LocationAwareDOMParser.cpp:32:49: error: uninitialized
const ‘LOCATION_DATA_HANDLER’ [-fpermissive]
src/XercesExtensions/LocationInfoDataHandler.h:32:7: note: ‘const class
XercesExt::LocationInfoDataHandler’ has no user-provided default constructor

I fixed it by removing the 'const' qualifier.
```

Original issue reported on code.google.com by `saltyho...@gmail.com` on 10 Mar 2012 at 10:28