configure.ac: Bump version to 1.3.93
configure.ac: Bump version to 1.3.93

This is the release candidate.

tulcod/wayland,eyolfson/wayland,sir-murray/wayland,mchalupa/wayland,abooij/wayland,eyolfson/wayland,mchalupa/wayland,mchalupa/wayland,sir-murray/wayland,tulcod/wayland,tulcod/wayland,abooij/wayland,bitfactor/wayland,abooij/wayland,bitfactor/wayland,sir-murray/wayland,eyolfson/wayland,bitfactor/wayland