test/system: Re-align

All the other Bats files for the system tests are indented by two
spaces, not four.

This will make the subsequent commit easier to read.

test/system/000-setup.bats

@@ -18,27 +18,27 @@
 load 'libs/helpers'
 
 @test "test suite: Set up" {
-    local os_release="$(find_os_release)"
-    local system_id="$(get_system_id)"
-    local system_version="$(get_system_version)"
+  local os_release="$(find_os_release)"
+  local system_id="$(get_system_id)"
+  local system_version="$(get_system_version)"
 
-    _setup_environment
-    # Cache the default image for the system
-    _pull_and_cache_distro_image "$system_id" "$system_version" || false
-    # Cache all images that will be needed during the tests
-    _pull_and_cache_distro_image arch latest || false
-    _pull_and_cache_distro_image fedora 34 || false
-    _pull_and_cache_distro_image rhel 8.7 || false
-    _pull_and_cache_distro_image ubuntu 16.04 || false
-    _pull_and_cache_distro_image ubuntu 18.04 || false
-    _pull_and_cache_distro_image ubuntu 20.04 || false
-    _pull_and_cache_distro_image busybox || false
-    # If run on Fedora Rawhide, cache 2 extra images (previous Fedora versions)
-    local rawhide_res="$(awk '/rawhide/' $os_release)"
-    if [ "$system_id" = "fedora" ] && [ -n "$rawhide_res" ]; then
-        _pull_and_cache_distro_image fedora "$((system_version-1))" || false
-        _pull_and_cache_distro_image fedora "$((system_version-2))" || false
-    fi
+  _setup_environment
+  # Cache the default image for the system
+  _pull_and_cache_distro_image "$system_id" "$system_version" || false
+  # Cache all images that will be needed during the tests
+  _pull_and_cache_distro_image arch latest || false
+  _pull_and_cache_distro_image fedora 34 || false
+  _pull_and_cache_distro_image rhel 8.7 || false
+  _pull_and_cache_distro_image ubuntu 16.04 || false
+  _pull_and_cache_distro_image ubuntu 18.04 || false
+  _pull_and_cache_distro_image ubuntu 20.04 || false
+  _pull_and_cache_distro_image busybox || false
+  # If run on Fedora Rawhide, cache 2 extra images (previous Fedora versions)
+  local rawhide_res="$(awk '/rawhide/' $os_release)"
+  if [ "$system_id" = "fedora" ] && [ -n "$rawhide_res" ]; then
+    _pull_and_cache_distro_image fedora "$((system_version-1))" || false
+    _pull_and_cache_distro_image fedora "$((system_version-2))" || false
+  fi
 
-    _setup_docker_registry
+  _setup_docker_registry
 }