debian/rules: Re-enable PIE hardening

We disabled that in 2016, but it does not seem necessary anymore,
seems to break LTO and possibly reduces security.

debian/rules

@@ -8,7 +8,7 @@ export TIME:=$(shell $(DATE_CMD) --date="$(DATETIME)" "+%H:%M:%S")
 export DEB_CFLAGS_MAINT_APPEND=-Wno-write-strings \
                                -DDATE=\""$(DATE)"\" \
                                -DTIME=\""$(TIME)"\"
-export DEB_BUILD_MAINT_OPTIONS=hardening=+all,-pie
+export DEB_BUILD_MAINT_OPTIONS=hardening=+all
 export PYBUILD_NAME=apt
 
 BUILDDIR3 := $(shell pybuild --print build_dir --interpreter python3)