Create deb_convert_i386_to_amd64.sh

Simple DEB packages arch conversion
(changes $arch in control.tar.gz from i386 to amd64)

Usage: deb_convert_i386_to_amd64.sh PACKAGENAME_VERSION  (without $arch and '.deb')

Eg. for python-setproctitle_1.1.6-1_i386.deb you would launch:
deb_convert_i386_to_amd64.sh python-setproctitle_1.1.6-1