Fix wrong common_samples.bkl include path in animate sample bakefile.

Surprisingly, the wrong path somehow worked all this time and still works in
some installation, but not all of them. Using the correct path shouldn't hurt
though.

Closes #15570.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@74979 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775