Don’t break when specifying doc options, but not appledoc ones. Fixes #906.

lib/cocoapods/generator/documentation.rb

@@ -145,7 +145,7 @@ module Pod
       #
       def spec_appledoc_options
         return [] unless specification.documentation
-        specification.documentation[:appledoc]
+        specification.documentation[:appledoc] || []
       end
 
       # @return [Array<String>] The list of the appledoc options followed by

spec/unit/generator/documentation_spec.rb

@@ -14,6 +14,11 @@ module Pod
       @doc_installer.public_headers.sort.should == %w[ Classes/Banana.h ].sort
     end
 
+    it 'returns an empty array in case there are no appledoc options specified' do
+      @doc_installer.specification.stubs(:documentation).returns({})
+      @doc_installer.spec_appledoc_options.should == []
+    end
+
     it 'returns the Pod documentation options' do
       expected = [
         '--project-name', 'BananaLib 1.0',