Merge pull request #1550 from bcoca/1549_lininfile_backup_bug

fixes #1549

library/lineinfile

@@ -143,7 +143,7 @@ def present(module, dest, regexp, line, insertafter, create, backup):
         changed = True
 
     if changed:
-        if backup:
+        if backup and os.path.exists(dest):
             module.backup_local(dest)
         f = open(dest, 'wb')
         f.writelines(lines)