Disable spring example project until #448 is fixed

Author: aslakhellesoy

pom.xml

@@ -397,7 +397,7 @@
         <profile>
             <id>release-sign-artifacts</id>
             <modules>
-                <module>examples/spring-txn</module>
+                <!--<module>examples/spring-txn</module>-->
                 <module>examples/java-calculator</module>
                 <module>examples/groovy-calculator</module>
                 <module>examples/scala-calculator</module>