tests: fix daemon version in isDaemonNewer function

Since ad8a4b380e, the version printer returns "nix (Lix, like Nix) 2.x",
hence the `daemonVersion` was being set to the string "like".

Using `compareVersions` with a letter compares them lexicographically:

   builtins.compareVersions "like" "2.12pre20230103"  // => -1
   builtins.compareVersions "like" "2.16.0"           // => -1

This caused that `isDaemonNewer` always returned 1, falsy in Bash terms.
Therefore, the test suite skipped those tests where they use it.

Fixes #324

Change-Id: If6682515bf0bf8b8add641af9a4e98b50a9acb51

tests/functional/common/vars-and-functions.sh.in

@@ -146,7 +146,8 @@ fi
 isDaemonNewer () {
   [[ -n "${NIX_DAEMON_PACKAGE:-}" ]] || return 0
   local requiredVersion="$1"
-  local daemonVersion=$($NIX_DAEMON_PACKAGE/bin/nix daemon --version | cut -d' ' -f3)
+  local versionOutput=$($NIX_DAEMON_PACKAGE/bin/nix daemon --version)
+  local daemonVersion=${versionOutput##* }
   [[ $(nix eval --expr "builtins.compareVersions ''$daemonVersion'' ''$requiredVersion''") -ge 0 ]]
 }