ProjectConceptor: drop $jobArgs in BUILD(). See #2445

This is required with the current makefile because the "plugins"
target fails to build if we don't build the "app" target first.

haiku-apps/projectconceptor/projectconceptor-0.1.0.recipe

@@ -59,7 +59,7 @@ defineDebugInfoPackage projectconceptor \
 
 BUILD()
 {
-	make -C src OBJ_DIR=objects app plugins $jobArgs
+	make -C src OBJ_DIR=objects app plugins
 }
 
 INSTALL()