devel/ipython: Remove leftover artifact after removing GCC dependency

The ex script was supposed to add two lines in all scripts to set
LD_LIBRARY_PATH and since we don't need to set that anymore (see removed
GCC dependency in ports r476502), the whole script is now irrelevant.

Reported by: antoine
Reviewed by: koobs
Approved by: koobs (python)
Differential Revision: https://reviews.freebsd.org/D16605