software/theia: Fix logo.png installation

In older theia versions `~/srv/frontend-static/logo.png` was a symlink
to the actual logo file. Now the logo is copied into `frontend-static`
but a simple `cp -f` does not behave as expected when the destination
already exists and is a symbolic link:
- if the symlink is valid, the file is copied to the symlink target
- if the symlink is broken, the copy command fails

So the destination must be removed before copying.

software/theia/buildout.hash.cfg

@@ -15,7 +15,7 @@
 
 [instance]
 filename = instance.cfg.in
-md5sum = f3aac995aa1129ca58f9a92851ad7091
+md5sum = c9eccc7d972bc939b552672331b5a56e
 
 [yarn.lock]
 filename = yarn.lock

software/theia/instance.cfg.in

@@ -230,7 +230,7 @@ recipe = plone.recipe.command
 filename = logo.png
 full-path = $${directory:frontend-static}/$${:filename}
 command =
-  cp -f ${logo.png:output} $${:full-path}
+  cp --remove-destination ${logo.png:output} $${:full-path}
 stop-on-error = true
 
 [frontend-instance-slapos.css]