Fix snippets

Author: yihanzhen

google-cloud-examples/src/main/java/com/google/cloud/examples/spanner/snippets/DatabaseAdminClientSnippets.java

@@ -74,9 +74,9 @@ public Database createDatabase(String instanceId, String databaseId) {
     Database db;
     try {
       db = op.get();
-    } catch (Exception e) {
-      throw SpannerExceptionFactory.newSpannerException(e);
-    }
+    } catch (ExecutionException | InterruptedException e) {
+      throw e.getCause();
+    } 
     // [END createDatabase]
     return db;
   }