fix filename/suffix logic (#24)

Author: slayoo

open_atmos_jupyter_utils/show_plot.py

@@ -21,8 +21,9 @@ def save_and_make_link(fig, filename=None):
     """ saves a figure as pdf and returns a Jupyter display()-able click-to-download widget """
     temporary_files = [
         TemporaryFile(suffix=suffix, filename=(
-            filename if filename is None or not filename.endswith('.pdf') else filename[:-4]
-        ) + suffix)
+            filename if filename is None else
+            ((filename if not filename.endswith('.pdf') else filename[:-4]) + suffix)
+        ))
         for suffix in ('.pdf', '.svg')
     ]
     for temporary_file in temporary_files: