To switch your current svn checkout to the new svn location on sorceforge go to the directory were you checkced out and do:
For new svn(subversion) versions:
svn relocate https://svn.code.sf.net/p/megaglest/code/trunk
For older svn(subversion) versions
svn switch --relocate https://megaglest.svn.sourceforge.net/svnroot/megaglest/trunk https://svn.code.sf.net/p/megaglest/code/trunk