Minor fixes in Makefile and prepare_deployment.sh

* Remove $(build_dir).zircon now that build unification is complete.

* Fix prepare_deployment.sh, now that `fx build` fails if the working
  directory is not inside FUCHSIA_DIR.

* Add a missing double quote in `make help`.

Change-Id: I325d6773dba687c587164a7f4e04a871341c8327
diff --git a/Makefile b/Makefile
index e8a68e7..da85aec 100644
--- a/Makefile
+++ b/Makefile
@@ -30,7 +30,6 @@
 else
 build_dir := $(FUCHSIA_DIR)/$(file < $(FUCHSIA_DIR)/.fx-build-dir)
 bin := $(build_dir)/host_x64$\
-	:$(build_dir).zircon/tools$\
 	:$(FUCHSIA_DIR)/prebuilt/third_party/rust_tools/$(host_platform)/bin
 etc := $(FUCHSIA_DIR)
 fidl := $(FUCHSIA_DIR)/sdk/fidl$\
@@ -51,7 +50,7 @@
 	@echo "    frontend   Build the frontend/dist bundle using webpack."
 	@echo "               For more build options: cd frontend && npm run."
 	@echo "    backend    Build the $(server) server binary."
-	@echo "    test       Build and run all tests.
+	@echo "    test       Build and run all tests."
 	@echo "    run        Run the fidlbolt server on \$$PORT."
 	@echo "               Set VERBOSE=1 to enable verbose logging."
 	@echo "               Set DEPLOYMENT=1 to use files in ./deployment instead"
diff --git a/prepare_deployment.sh b/prepare_deployment.sh
index 8aed3c3..b53851e 100755
--- a/prepare_deployment.sh
+++ b/prepare_deployment.sh
@@ -89,7 +89,9 @@
 )
 
 step "Building targets in $FUCHSIA_DIR"
+pushd "$FUCHSIA_DIR"
 fx build "${binaries[@]/#/host_x64/}"
+popd
 
 step "Cleaning ./deployment"
 cd "$(dirname "$0")"