title: Autolayout is complaining about leading/trailing space for UIImageView
body: <p>I have a UICollectionViewCell in storyboard that has a UIImageView inside of it.</p>
  
  <p>The <code>UICollectionViewCell size is width: 189, height: 239</code> . The ImageView has the following constraints:</p>
  
  <pre><code>Trailing Space to cell = 31
  Leading Space to cell = 31
  Bottom Space to cell =  25
  Top Space to cell = 31
  </code></pre>
  
  <p>I receive the following error when running:</p>
  
  <blockquote>
    <p>2014-11-28 19:53:33.934 AppName[1585:35698] Unable to
    simultaneously satisfy constraints.   Probably at least one of the
    constraints in the following list is one you don't want. Try this: (1)
    look at each constraint and try to figure out which you don't expect;
    (2) find the code that added the unwanted constraint or constraints
    and fix it. (Note: If you're seeing
    NSAutoresizingMaskLayoutConstraints that you don't understand, refer
    to the documentation for the UIView property
    translatesAutoresizingMaskIntoConstraints)  (</p>
  </blockquote>
  
  <pre><code>"&lt;NSLayoutConstraint:0x7fa4a0d75220 H:[UIImageView:0x7fa4a0d743e0]-(31)-|   (Names: '|':UIView:0x7fa4a0d73d40 )&gt;",
  "&lt;NSLayoutConstraint:0x7fa4a0d752c0 H:|-(32)-[UIImageView:0x7fa4a0d743e0]   (Names: '|':UIView:0x7fa4a0d73d40 )&gt;",
  "&lt;NSAutoresizingMaskLayoutConstraint:0x7fa4a0d567a0 h=--&amp; v=--&amp; H:[UIView:0x7fa4a0d73d40(50)]&gt;" )
  </code></pre>
  
  <blockquote>
    <p>Will attempt to recover by breaking constraint 
    NSLayoutConstraint:0x7fa4a0d75220
    H:[UIImageView:0x7fa4a0d743e0]-(31)-|   (Names:
    '|':UIView:0x7fa4a0d73d40 )></p>
    
    <p>Make a symbolic breakpoint at UIViewAlertForUnsatisfiableConstraints
    to catch this in the debugger. The methods in the
    UIConstraintBasedLayoutDebugging category on UIView listed in
     may also be helpful.</p>
  </blockquote>
  
  <p>I tried changing the leading/trailing values in all kinds of ways (tried even/odd numbers) with no success. What is causing this?</p>