Eliminate Conda hack forcing /tmp as temp directory.

It wasn't playing well with Docker inside of Conda, new Conda packages shouldn't require this, and older Conda packages need to be caught and rebuilt for Galaxy anyway.

planemo/galaxy/config.py

@@ -569,17 +569,7 @@ def _config_directory(ctx, **kwds):
     created_config_directory = False
     if not config_directory:
         created_config_directory = True
-        config_directory = mkdtemp()
-        # the following makes sure the transient config_dir path is short
-        # enough for conda linking (https://github.com/conda/conda-build/pull/877)
-        if len(config_directory) > 20:
-            try:
-                short_config_directory = mkdtemp(dir="/tmp")
-                os.rmdir(config_directory)
-                config_directory = short_config_directory
-            except OSError:
-                # path doesn't exist or permission denied, keep the long config_dir
-                pass
+        config_directory = os.path.realpath(mkdtemp())
     try:
         yield config_directory
     finally: