wayland: Call eglTerminate before destroying wl_display, not after

The eglTerminate code in Mesa will try to destroy the wl_drm object
which involves using data structures in the wl_display. Cogl was
disconnecting the display before calling eglTerminate which meant that
this would end up accessing potentially garbage data.

https://bugzilla.gnome.org/show_bug.cgi?id=705591

Reviewed-by: Robert Bragg <robert@linux.intel.com>
Fix the help string for --enable-standalone

The help string had the wrong name presumably resulting from a cut and
paste error of the --enable-debug option.

Reviewed-by: Robert Bragg <robert@linux.intel.com>
Reviewed-by: Damien Lespiau <damien.lespiau at intel.com>
Fix the documented default value for --enable-cogl-path

As far as I can tell --enable-cogl-path is enabled by default but the
help string for it was suggesting otherwise.

Reviewed-by: Robert Bragg <robert@linux.intel.com>