fix stage-qa findings for 1.41.0 (at least):
 - invalid shebangs for .py files

Index: Makefile
===================================================================
--- Makefile	(revision 525030)
+++ Makefile	(working copy)
@@ -74,6 +74,12 @@
 _RUST_STD_BOOTSTRAP=	${BOOTSTRAPS_DATE_${ARCH}:U${BOOTSTRAPS_DATE}}/rust-std-${RUST_BOOTSTRAP_VERSION_${ARCH}:U${RUST_BOOTSTRAP_VERSION}}-${_RUST_TARGET}
 _CARGO_BOOTSTRAP=	${BOOTSTRAPS_DATE_${ARCH}:U${BOOTSTRAPS_DATE}}/cargo-${CARGO_BOOTSTRAP_VERSION_${ARCH}:U${CARGO_BOOTSTRAP_VERSION}}-${_RUST_TARGET}
 
+SOURCES_USES+=		shebangfix
+	SHEBANG_FILES+="\
+		src/libcore/unicode/printable.py \
+		src/libcore/unicode/unicode.py \
+		"
+
 .include <bsd.port.pre.mk>
 
 .if exists(${PATCHDIR}/libgit2)