Restrict the install:module="neon_gnomevfs" hack to --with-webdav=neon

...as the underlying problem, according to
<https://bz.apache.org/ooo/show_bug.cgi?id=84676> "mixing neon and the hidden
embedded contents old [sic] another neon inside libhttp.so of gnome-vfs2 is
unreliable," presumably does not affect --with-webdav=serf

Change-Id: I2abfeaeac5174a735f46b2838bd84dda0af9a487

postprocess/CustomTarget_registry.mk

@@ -329,10 +329,12 @@ postprocess_DRIVERS += ado
 endif
 ifneq ($(WITH_WEBDAV),)
 postprocess_FILES_main += $(postprocess_MOD)/org/openoffice/ucb/Configuration-neon.xcu
+ifeq ($(WITH_WEBDAV),neon)
 ifeq ($(ENABLE_GNOMEVFS),TRUE)
 postprocess_FILES_main += $(postprocess_MOD)/org/openoffice/ucb/Configuration-neon_gnomevfs.xcu
 endif
 endif
+endif
 ifeq ($(ENABLE_EVOAB2),TRUE)
 postprocess_FILES_main += $(call gb_XcuModuleTarget_get_target,connectivity/registry/evoab2)/org/openoffice/Office/DataAccess/Drivers-evoab2.xcu
 postprocess_FILES_main += $(postprocess_MOD)/org/openoffice/Office/DataAccess-evoab2.xcu