Makefile fix: prevent sed from leaving a backup file

Makefile

@@ -153,7 +153,7 @@ dist: all
 		rm dist/workdir/extcap/tracee-capture.sh; \
 	fi
 
-	@sed -i'' -e 's/VERSION_PLACEHOLDER/$(TRACEESHARK_VERSION)/g' dist/workdir/extcap/tracee-capture.py
+	@sed -i '' -e 's/VERSION_PLACEHOLDER/$(TRACEESHARK_VERSION)/g' dist/workdir/extcap/tracee-capture.py
 
 	$(eval WS_VERSION := $(shell wireshark/build/run/wireshark --version | grep -o -E "Wireshark [0-9]+\.[0-9]+\.[0-9]+" | grep -o -E "[0-9]+\.[0-9]+\.[0-9]+"))
 	@echo $(WS_VERSION) > dist/workdir/ws_version.txt