Gsettings schema corrections

git-svn-id: svn+ssh://svn.gnucash.org/repo/gnucash/trunk@23272 57a11ea4-9604-0410-9ed3-97b8803252fd
Gnc-Prefs: add code to migrate settings from gconf to gsettings at runtime

git-svn-id: svn+ssh://svn.gnucash.org/repo/gnucash/trunk@23273 57a11ea4-9604-0410-9ed3-97b8803252fd