No fpicker needed for non-DESKTOP surely?

Sure, not a lot of code, but best to not even compile it, to catch
eventual usage attempts.

Change-Id: I7462ea9a5fbe6080fcec2f424d1a1b80ad0afe21

RepositoryModule_host.mk

@@ -52,7 +52,7 @@ $(eval $(call gb_Module_add_moduledirs,libreoffice,\
 	filter \
 	$(call gb_Helper_optional,DBCONNECTIVITY,forms) \
 	formula \
-	fpicker \
+	$(call gb_Helper_optional,DESKTOP,fpicker) \
 	framework \
 	$(call gb_Helper_optional,DESKTOP,helpcompiler) \
 	$(call gb_Helper_optional,HELP,helpcontent2) \

postprocess/Rdb_services.mk

@@ -42,7 +42,7 @@ $(eval $(call gb_Rdb_add_components,services,\
 	filter/source/xsltdialog/xsltdlg \
 	filter/source/xsltfilter/xsltfilter \
 	formula/util/for \
-	fpicker/source/office/fps_office \
+	$(call gb_Helper_optional,DESKTOP,fpicker/source/office/fps_office) \
 	framework/util/fwk \
 	framework/util/fwl \
 	framework/util/fwm \