Bug with wiki TOC (BB-1007)

From a customer support case:

I've got an issue with TOC inside a page in a directory. On page [1] I have placed a <<toc>> element and I expected it to list all headings in the current page. However instead of:

https://bitbucket.org/USER/REPO/wiki/Examples/TEST#!valid-examples

I get links simmilar to:

https://bitbucket.org/USER/REPO/wiki/Examples/Examples/TEST#!valid-examples

This means there is an extra "Examples" part.