Fix mislocated ipython bindings by not moving them (RHBZ #1554741)
o There's no real justification to move ipython bindings when they're imported
as python modules by the user anyway.
o Before this change, importing the powerline.bindings.ipython.since_5 module
wouldn't work because it couldn't locate the other two files that were
moved into /usr/share/powerline
o https://powerline.readthedocs.io/en/master/usage/other.html#ipython-prompt