Use new convention for python shell name

The name of the dedicated python shells are now using the buffer name
without extension.
This avoid conflicts with the way python.el handles dedicated shells
(see jorgenschaefer#1328).

elpy-shell.el

@@ -256,7 +256,9 @@ if ARG is negative or 0, disable the use of a dedicated shell."
     (if (<= arg 0)
         (kill-local-variable 'python-shell-buffer-name)
       (setq-local python-shell-buffer-name
-                  (format "Python[%s]" (buffer-name))))))
+                  (format "Python[%s]"
+                          (file-name-sans-extension
+                          (buffer-name)))))))
 
 (defun elpy-shell-set-local-shell (&optional shell-name)
   "Associate the current buffer to a specific shell.
@@ -276,12 +278,14 @@ shell (often \"*Python*\" shell)."
                                "Global"))
          (shell-names (cl-loop
                 for buffer in (buffer-list)
-                for buffer-name = (substring-no-properties (buffer-name buffer))
+                for buffer-name = (file-name-sans-extension (substring-no-properties (buffer-name buffer)))
                 if (string-match "\\*Python\\[\\(.*?\\)\\]\\*" buffer-name)
                 collect (match-string 1 buffer-name)))
          (candidates (remove current-shell-name
-                          (delete-dups
-                           (append (list (buffer-name) "Global") shell-names))))
+                           (delete-dups
+                           (append (list (file-name-sans-extension
+                                          (buffer-name)) "Global")
+                                   shell-names))))
          (prompt (format "Shell name (current: %s): " current-shell-name))
          (shell-name (or shell-name (completing-read prompt candidates))))
     (if (string= shell-name "Global")