Update install_mapserver.sh (ticket 2329)
Update install_mapserver.sh (ticket 2329)

Version of regex library installed doesn't like \- in the character sets for directories and filenames. The regex compiles fine but doesn't evaluate correctly. Moving it as just - to the front of those character sets seems to fix things using the nightly OSGeo ISO.
astroidex/OSGeoLive,OSGeo/OSGeoLive,OSGeo/OSGeoLive,kalxas/OSGeoLive,kalxas/OSGeoLive,OSGeo/OSGeoLive,kalxas/OSGeoLive,astroidex/OSGeoLive,OSGeo/OSGeoLive,OSGeo/OSGeoLive,astroidex/OSGeoLive,astroidex/OSGeoLive,OSGeo/OSGeoLive,kalxas/OSGeoLive,kalxas/OSGeoLive,kalxas/OSGeoLive,kalxas/OSGeoLive,astroidex/OSGeoLive,astroidex/OSGeoLive,OSGeo/OSGeoLive