Commander needn't accumulate configuration

Commander had version/destination solely to incrementally accumulate CLI
options. Simpler to configure in one shot.

Clarifies responsibility and lets us introduce things like
`abbreviated_version` in one spot - Configuration.

test/commander_test.rb

@@ -2,23 +2,15 @@ require "test_helper"
 
 class CommanderTest < ActiveSupport::TestCase
   setup do
-    @mrsk = Mrsk::Commander.new config_file: Pathname.new(File.expand_path("fixtures/deploy_with_roles.yml", __dir__))
+    @mrsk = Mrsk::Commander.new.tap do |mrsk|
+      mrsk.configure config_file: Pathname.new(File.expand_path("fixtures/deploy_with_roles.yml", __dir__))
+    end
   end
 
   test "lazy configuration" do
     assert_equal Mrsk::Configuration, @mrsk.config.class
   end
 
-  test "commit hash as version" do
-    assert_equal `git rev-parse HEAD`.strip, @mrsk.config.version
-  end
-
-  test "commit hash as version but not in git" do
-    @mrsk.expects(:system).with("git rev-parse").returns(nil)
-    error = assert_raises(RuntimeError) { @mrsk.config }
-    assert_match /no git repository found/, error.message
-  end
-
   test "overwriting hosts" do
     assert_equal [ "1.1.1.1", "1.1.1.2", "1.1.1.3", "1.1.1.4" ], @mrsk.hosts