[all] Trying hard to please the CI gods

Previously export RUBYOPT=-Ispec was masking the
fact that "lib" and "spec" dirs weren't added to
rspec's loadpath. This caused rake spec to fail
when RUBYOPT=-Ispec wasn't set

spec/spec_helper.rb

@@ -4,7 +4,7 @@
 require 'dm-core'
 
 # Support running specs with 'rake spec' and 'spec'
-$LOAD_PATH.unshift(File.join('lib'))
+$LOAD_PATH.unshift('lib') unless $LOAD_PATH.include?('lib')
 
 require 'dm-migrations'
 require 'dm-migrations/migration_runner'

tasks/spec.rb

@@ -8,6 +8,7 @@
   Spec::Rake::SpecTask.new(:spec) do |t|
 
     t.spec_opts << '--options' << 'spec/spec.opts' if File.exists?('spec/spec.opts')
+    t.libs << 'lib' << 'spec' # needed for CI rake spec task, duplicated in spec_helper
 
     begin
       require 'rcov'