[fix] spec files not ends with "_spec.rb" (#3879)

* [modify] rename specs not ends with "_spec.rb"

* [modify] move support file under "spec/support/"

* [modify] exit on failure if spec files not ended with "_spec.rb" are found

.travis.d/split_specs.rb

@@ -12,7 +12,14 @@
   opt.parse!(ARGV)
 end
 
-spec_files = Dir.glob("#{ARGV.first || "spec"}/**/*.rb")
+count = `find spec -name '*.rb' | fgrep -v spec/factories/ | fgrep -v spec/support/ | fgrep -v _spec.rb | wc -l`
+count = count.strip.to_i
+if count > 1
+  puts "there are spec files which aren't ended with \"_spec.rb\""
+  exit!
+end
+
+spec_files = Dir.glob("#{ARGV.first || "spec"}/**/*_spec.rb")
 excludes.each do |exclude|
   spec_files.reject! { |file| file.include?(exclude) }
 end