svx: revert usage of "dbtools" headers

The root cause for build failure was fixed by
41cc83d7

Change-Id: I9502f668e3f27a99aa278396bee36de131706d90

svx/Library_svxcore.mk

@@ -377,10 +377,6 @@ $(eval $(call gb_Library_add_exception_objects,svxcore,\
 
 ifneq (,$(filter DBCONNECTIVITY,$(BUILD_TYPE)))
 
-$(eval $(call gb_Library_use_headers,svxcore,\
-	dbtools \
-))
-
 $(eval $(call gb_Library_add_exception_objects,svxcore,\
     svx/source/fmcomp/dbaexchange \
     svx/source/fmcomp/fmgridcl \