Bug 1368264 - Fix missing RUST_PROGRAMS entry in if-condition r=froydnj

Final target Rust programs are currently not picked up and
symlinked/copied to ${objdir}/dist/bin because the RUST_PROGRAMS output
variable is missing from the if-condition.

This change causes Rust binaries from RUST_PROGRAMS to be placed alongside
the other final target programs.

MozReview-Commit-ID: 5OIH1UMmCq2

--HG--
extra : rebase_source : cfcff21e9371b920c895ad27df344008962d7471

config/makefiles/target_binaries.mk

@@ -7,7 +7,7 @@
 
 ifndef NO_DIST_INSTALL
 
-ifneq (,$(strip $(PROGRAM)$(SIMPLE_PROGRAMS)))
+ifneq (,$(strip $(PROGRAM)$(SIMPLE_PROGRAMS)$(RUST_PROGRAMS)))
 PROGRAMS_EXECUTABLES = $(SIMPLE_PROGRAMS) $(PROGRAM) $(RUST_PROGRAMS)
 PROGRAMS_DEST ?= $(FINAL_TARGET)
 PROGRAMS_TARGET := target