fix some code styling issues

lib/common/common_helper.rb

@@ -41,7 +41,7 @@ $LOAD_PATH.unshift(MODELS_LIB_DIR)
 
 def kali_linux?
   begin
-    File.readlines("/etc/debian_version").grep(/^kali/i).any?
+    File.readlines('/etc/debian_version').grep(/^kali/i).any?
   rescue
     false
   end
@@ -54,7 +54,7 @@ def require_files_from_directory(absolute_dir_path, files_pattern = '*.rb')
   files = Dir[File.join(absolute_dir_path, files_pattern)]
 
   # Files in the root dir are loaded first, then those in the subdirectories
-  files.sort_by { |file| [file.count("/"), file] }.each do |f|
+  files.sort_by { |file| [file.count('/'), file] }.each do |f|
     f = File.expand_path(f)
     #puts "require #{f}" # Used for debug
     require f