Correct a typo in pycall_spec.rb

Author: felixonmars

spec/pycall_spec.rb

@@ -155,7 +155,7 @@
       expect(out.chomp).to eq('true')
     end
 
-    it 'returns false if alreadly initialized' do
+    it 'returns false if already initialized' do
       out, err, status = ruby(<<RUBY)
 require 'pycall'
 PyCall.init