title: Not possible to set the Jenkins' XCode plugin to use a specified keychain?
body: <p>The XCode plugin seems to make the assumption that only keychains from the user jenkins can be used for signing XCode builds.</p>
  
  <p>There is a section called Keychain path, however if I enter into there the following,<br>
       <code>/Users/Me/Library/Keychains/login.keychain</code> </p>
  
  <p>then the build logshows the following:</p>
  
  <pre><code>"Will not set default: file /Users/Shared/Jenkins/Library/Keychains/Users/Me/Library/Keychains/login.keychain does not exist"
  </code></pre>
  
  <p>So the plugin has appended what I entered onto  /Users/Shared/Jenkins/Library/Keychains/.</p>
  
  <p>If I leave it as the default value of  </p>
  
  <pre><code>${HOME}/Library/Keychains/login.keychain 
  </code></pre>
  
  <p>then the build log says:</p>
  
  <pre><code>"Will not set default: file /Users/Shared/Jenkins/Library/Keychains/login.keychain does not exist"
  </code></pre>
  
  <p>Thus the XCode build plugin is forcing users to be Jenkins - which means its necessary to set up a keychain as the user Jenkins?
  In which case, how is this done - when Jenkins is installed onto a Mac it by default creates a user called jenkins but AFAIK this is an anonymous user and its not actually possible to logon to the machine as the user jenkins.
  Therefore how are keychains for the user jenkins created?</p>
  
  <p>Why does the plugin force this, and why is none of this aspect of things documented?</p>
  
  <p>If I can use a keychain from a different user then how? - its not documented.</p>