[MERGE] Fix for Bug 129299, BZR_PLUGIN_PATH should ignore trailiing slashes.

[Robert Collins]

Robert Collins has voted resubmit.
Status is now: Resubmit
Comment:
Couple of things. If load_from_path is now accepting paths with '/', 
then you shouldn't need to santise BZR_PLUGINS_PATH - the lower level 
check will suffice. I like the test that the path is set from the value 
of BZR_PLUGINS_PATH - thank you for adding that. Finally, your test that 
load_from_path works with '/' is clearly cargo culted - I suggest you 
read through it once and make sure the comments match what your test 
actually does - the don't currently.

For details, see: 
http://bundlebuggy.aaronbentley.com/request/%3C46B9CB85.1050608%40latte.ca%3E