title: shutil.make_archive issue - don't want directories included in zip file
body: <p>I am trying to archive 2 files but not the full path leading up to the two files. Hopefully someone can point me in the right direction:</p>
  
  <p>My directory structure is as follows. I only have two files which I want backed up.</p>
  
  <pre><code>/tmp
      my_stuff
          -hello.html
          -hello2.html
  </code></pre>
  
  <p>So per the documentation, shutil.make_archive can zip up entire directories. I am using the following command:</p>
  
  <pre><code>shutil.make_archive( base_name =  '/tmp/package',
                       format    =  'zip',
                       root_dir  =  '/tmp/my_stuff', 
                       base_dir  =  '/tmp/my_stuff' )
  </code></pre>
  
  <p>This command successfully creates the zip file however when I do "unzip package.zip from within the /tmp folder", I get the following:</p>
  
  <pre><code>➜  /tmp unzip package.zip
  Archive:  package.zip
     creating: tmp/my_stuff
    inflating: tmp/my_stuff/hello.html  
    inflating: tmp/my_stuff/hello2.html
  </code></pre>
  
  <p>It creates a duplicate "tmp" within tmp and a new folder called my_stuff and the 2 files. All I want is for it to extract the two files (without the directories). Any advice would be appreciated.</p>
  
  <p>Thanks</p>