BUG: fix conda_prefix check when not using conda (#380)

Closed #377.

Author: gregcaporaso

q2cli/util.py

@@ -13,10 +13,10 @@ class OutOfDisk(Exception):
 
 def get_app_dir():
     import os
-    conda_prefix = os.environ.get('CONDA_PREFIX')
+    conda_prefix = os.environ.get('CONDA_PREFIX', '')
     environment_cache = os.path.join(conda_prefix, 'var', 'q2cli')
-    if conda_prefix is not None and (os.access(conda_prefix, os.W_OK | os.X_OK)
-                                     or os.path.exists(environment_cache)):
+    if conda_prefix != '' and (os.access(conda_prefix, os.W_OK | os.X_OK)
+                               or os.path.exists(environment_cache)):
         return environment_cache
     else:
         import click