build: fix deprecated uses of configure_file

Using `configure_file` to copy files has been deprecated since Meson 0.64.0.
The intended replacement is the `fs.copyfile` method.

This removes the following deprecation warning that arises when a minimum
Meson version is specified:

``
Project [...] uses feature deprecated since '0.64.0': copy arg in configure_file. Use fs.copyfile instead
``

Change-Id: I09ffc92e96311ef9ed594343a0a16d51e74b114a

scripts/meson.build

@@ -8,12 +8,7 @@ configure_file(
   }
 )
 
-# https://github.com/mesonbuild/meson/issues/860
-configure_file(
-  input : 'nix-profile.sh.in',
-  output : 'nix-profile.sh.in',
-  copy : true,
-)
+fs.copyfile('nix-profile.sh.in')
 
 foreach rc : [ '.sh', '.fish', '-daemon.sh', '-daemon.fish' ]
   configure_file(