Applied bug fix from trunk r1350363.

Applied bug fix from jira issue - OFBIZ-4918 - Not able to add party rate.
User does not able to add party rate via Rate screen.
https://demo-trunk.ofbiz.apache.org/partymgr/control/EditPartyRates?partyId=admin
Thanks Deepak!

git-svn-id: https://svn.apache.org/repos/asf/ofbiz/branches/release10.04@1350365 13f79535-47bb-0310-9956-ffa450edef68

applications/accounting/script/org/ofbiz/accounting/rate/RateServices.xml

@@ -65,7 +65,7 @@ under the License.
         <make-value entity-name="RateAmount" value-field="newEntity"/>
         <set-pk-fields map="parameters" value-field="newEntity"/>
         <set-nonpk-fields map="parameters" value-field="newEntity"/>
-        <set field="newEntity.fromDate" value="${groovy: org.ofbiz.base.util.UtilDateTime.getDayStart(nowTimestamp)}" type="Timestamp"/>
+        <if-empty field="newEntity.fromDate"><now-timestamp field="newEntity.fromDate"/></if-empty>
         <clear-field field="newEntity.thruDate"/>
         <create-value value-field="newEntity"/>
     </simple-method>