Bug#372147: debian-policy: s/have s performance/???/; s/now prohib/is &/

[Justin Pryzby <justinpryzby@users.sourceforge.net>]

     Position independent code may have s performance penalty,
                                       ^^^
				       some?

     `/usr/X11R6/include/X11/' and `/usr/X11R6/lib/X11/' now prohibited;
                                                       ^^^
						       is