No need to bother with the MISCDUMMY file here

This rule failed if the MISCDUMMY file did not exist yet.

Change-Id: Ie9b1ecab2848f5ed2c459020a50013db691a9ca3

solenv/gbuild/Jar.mk

@@ -61,7 +61,7 @@ define gb_Jar__command
 	echo Manifest-Version: 1.0 > $(call gb_Jar_get_manifest_target,$(1)) && \
 	$(if $(JARCLASSPATH),echo "Class-Path: $(strip $(JARCLASSPATH))" >> $(call gb_Jar_get_manifest_target,$(1)) &&) \
 	echo "Solar-Version: $(RSCREVISION)" >> $(call gb_Jar_get_manifest_target,$(1)) && \
-	cat $(if $(MANIFEST),$(MANIFEST),$(gb_Helper_MISCDUMMY)) >> $(call gb_Jar_get_manifest_target,$(1)) && \
+	$(if $(MANIFEST),cat $(MANIFEST) >> $(call gb_Jar_get_manifest_target,$(1)) &&) \
 	mkdir -p $(dir $(2)) && cd $(call gb_Jar_get_workdir,$(1)) && \
 	$(gb_Jar_JARCOMMAND) cfm $(2) $(call gb_Jar_get_manifest_target,$(1)) \
 		META-INF $(PACKAGEROOTS) $(PACKAGEFILES) \