Defined function to get last db update and removed redundant code

lib/common/common_helper.rb

@@ -79,10 +79,17 @@ def missing_db_file?
   false
 end
 
+def last_update
+  date = nil
+  if File.exists?(LAST_UPDATE_FILE)
+    content = File.read(LAST_UPDATE_FILE)
+    date = Time.parse(content) rescue nil
+  end
+  return date
+end
+
 def update_required?
-  return true unless File.exist?(LAST_UPDATE_FILE)
-  content = File.read(LAST_UPDATE_FILE)
-  date = Time.parse(content) rescue Time.parse("2000-01-01")
+  date = last_update() or Time.parse('2000-01-01')
   return date < 5.days.ago
 end