ENH: Remove older customize std_vector.i file for R

Richard Beare's Fixes for std_vector have been integrated into the
upstream SWIG in version 2.0.10. There is not need for this extra
step, and the locally modified file.

Change-Id: I4e547cc3f1b8eb4f78e7a051f3ff0a0fff98f485
Merge topic 'SIMPLEITK-476_RemoveCustomRstd_vectorInterface'

d9cbcf69 ENH: Remove older customize std_vector.i file for R