recipes-graphics/wayland/agl-compositor_git.bb: Bump SRCREV

recipes-graphics/wayland/agl-compositor_git.bb: Bump SRCREV

Sync up with the latest octopus changes. Specifcally the following
changes have been added since the previous update:

- 6d41be723042cbbb6 compositor: Added layout_save/layout_restore
- 6678f58648dd18216 shell: Check for a valid ivi_surface
- b0dfbd7b26974a925 shell: Check for invalid outputs passed on when activating
- 39ad965461050db22 compositor: Fix memleak when disabling the output
- 77475e34bf7a1619b Add gitreview file for Optimistic Octopus branch
- 53a039ff1c4b05aaa ivi-compositor: Add support for multiple app_ids
- ce8dd33f3762e0ec4 meson: Deprecate waltham and inform users of that
- 6fd11a88c4d3c82e3 meson: Bump to version 0.0.21
- 4003cfb04b7bae04c shell: Reset the area activation

Change-Id: I87b404486b05e4b33903476ec9e2bd0ccbae194d
Signed-off-by: Marius Vlad <marius.vlad@collabora.com>
Reviewed-on: https://gerrit.automotivelinux.org/gerrit/c/AGL/meta-agl/+/28645
Reviewed-by: Jan-Simon Moeller <jsmoeller@linuxfoundation.org>
Tested-by: Jan-Simon Moeller <jsmoeller@linuxfoundation.org>