TEPHRA-267 Save the service reference in ReferenceCountedSupplier only if startup is successful

This closes #73

Signed-off-by: poorna <poorna@apache.org>
diff --git a/tephra-core/src/main/java/org/apache/tephra/coprocessor/ReferenceCountedSupplier.java b/tephra-core/src/main/java/org/apache/tephra/coprocessor/ReferenceCountedSupplier.java
index c929d29..876767a 100644
--- a/tephra-core/src/main/java/org/apache/tephra/coprocessor/ReferenceCountedSupplier.java
+++ b/tephra-core/src/main/java/org/apache/tephra/coprocessor/ReferenceCountedSupplier.java
@@ -53,8 +53,8 @@
 
         // Instance has not been instantiated
         T serviceInstance = instanceSupplier.get();
-        instance.set(serviceInstance);
         serviceInstance.startAndWait();
+        instance.set(serviceInstance);
       }
       int newCount = refCount.incrementAndGet();
       if (LOG.isDebugEnabled()) {