Clean up some gnome client warnings

sflphone-client-gnome/src/assistant.c

sflphone-client-gnome/src/call.c

sflphone-client-gnome/src/config/accountwindow.c

sflphone-client-gnome/src/config/accountwindow.h

sflphone-client-gnome/src/config/audioconf.c

sflphone-client-gnome/src/config/configwindow.c

sflphone-client-gnome/src/config/hooks-config.h

sflphone-client-gnome/src/contacts/calltree.c

sflphone-client-gnome/src/contacts/history.c

sflphone-client-gnome/src/contacts/searchbar.c

sflphone-client-gnome/src/dbus/dbus.c

sflphone-client-gnome/src/dbus/dbus.h

sflphone-client-gnome/src/toolbar.h