Docs: fix health response test

I managed to test the wrong snippet before pushing the last
commit.... This fixes the error in it.

docs/reference/getting-started.asciidoc

@@ -217,7 +217,7 @@ epoch      timestamp cluster       status node.total node.data shards pri relo i
 1475247709 17:01:49  elasticsearch green           1         1      0   0    0    0        0             0                  -                100.0%
 --------------------------------------------------
 // TESTRESPONSE[s/1475247709 17:01:49  elasticsearch/\\d+ \\d+:\\d+:\\d+ docs_integTestCluster/]
-// TESTRESPONSE[s/0             0                  -/0             \d+                  -/]
+// TESTRESPONSE[s/0             0                  -/0             \\d+                  -/]
 // TESTRESPONSE[_cat]
 
 We can see that our cluster named "elasticsearch" is up with a green status.