removed unusued jpa configuration file (because Spring configuration doesn't rely on it)

src/main/resources/META-INF/jpa-persistence.xml

-<persistence xmlns="http://java.sun.com/xml/ns/persistence"
-		xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-		xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd"
-		version="1.0">
-
-	<persistence-unit name="PetClinic" transaction-type="RESOURCE_LOCAL"/>
-</persistence>