title: conda fails to create environment
body: <p>How can I fix the following problem in conda where it fails to create a new environment?</p>
  
  <pre><code>conda create --name snowflakes biopython                                                                      130 ↵
  Fetching package metadata .........
  Solving package specifications: .
  
  Package plan for installation in environment /home/geoheil/.conda/envs/snowflakes:
  
  The following NEW packages will be INSTALLED:
  
      biopython:  1.68-np112py36_0
      mkl:        2017.0.1-0      
      numpy:      1.12.0-py36_0   
      openssl:    1.0.2k-1        
      pip:        9.0.1-py36_1    
      python:     3.6.0-0         
      readline:   6.2-2           
      setuptools: 27.2.0-py36_0   
      sqlite:     3.13.0-0        
      tk:         8.5.18-0        
      wheel:      0.29.0-py36_0   
      xz:         5.2.2-1         
      zlib:       1.2.8-3         
  
  Proceed ([y]/n)? y 
  
  mkl-2017.0.1-0 100% |######################################################################| Time: 0:00:14   9.39 MB/s
  numpy-1.12.0-p 100% |######################################################################| Time: 0:00:00   9.51 MB/s
  biopython-1.68 100% |######################################################################| Time: 0:00:00   9.26 MB/s
  ERROR conda.core.link:_execute_actions(330): An error occurred while installing package 'defaults::readline-6.2-2'.
  CondaError: Cannot link a source that does not exist. /opt/anaconda/pkgs/readline-6.2-2/lib/libhistory.a
  
  Attempting to roll back.
  
  
  
  CondaError: Cannot link a source that does not exist. /opt/anaconda/pkgs/readline-6.2-2/lib/libhistory.a
  </code></pre>