Removing tests for migrations

These were never run anyway (they don't have _spec.rb in their names)
and were obviously written when we had no idea what we were doing.
They're full of syntax errors and all sorts of stuff that just won't
work.  The best thing is to remove them so they don't confuse people!

spec/migrations/give_each_user_a_garden.spec

@@ -1,12 +0,0 @@
-require 'spec_helper'
-
-describe 'new gardens' do
-  it "should have 'my garden' for each user" do
-    (1..3).each do |i|
-      @user = User.find_by_username("test#{i}")
-      @garden = Garden.find(:name => "My Garden", :user_id => @user.id)
-      @garden.should_exist
-      @garden.slug.should == "test#{i}-my-garden"
-    end
-  end
-end

spec/migrations/set_up_test_users.spec

@@ -1,10 +0,0 @@
-require 'spec_helper'
-
-describe 'test users' do
-  it 'should have 3 test users' do
-    (1..3).each do |i|
-      @user = User.find_by_username("test#{i}")
-      @user.email.should == "test#{i}@example.com"
-    end
-  end
-end