PHOENIX-4672 Align the kerberos principal config keys

Fix the configuration keys in a manner that won't break users
who are using the 'old' name.
diff --git a/phoenix-core/src/main/java/org/apache/phoenix/query/QueryServices.java b/phoenix-core/src/main/java/org/apache/phoenix/query/QueryServices.java
index add756e..0a506ac 100644
--- a/phoenix-core/src/main/java/org/apache/phoenix/query/QueryServices.java
+++ b/phoenix-core/src/main/java/org/apache/phoenix/query/QueryServices.java
@@ -234,7 +234,8 @@
     public static final String QUERY_SERVER_KEYTAB_FILENAME_ATTRIB = "phoenix.queryserver.keytab.file";
     public static final String QUERY_SERVER_HTTP_KEYTAB_FILENAME_ATTRIB = "phoenix.queryserver.http.keytab.file";
     public static final String QUERY_SERVER_KERBEROS_PRINCIPAL_ATTRIB = "phoenix.queryserver.kerberos.principal";
-    public static final String QUERY_SERVER_KERBEROS_HTTP_PRINCIPAL_ATTRIB = "phoenix.queryserver.kerberos.http.principal";
+    public static final String QUERY_SERVER_KERBEROS_HTTP_PRINCIPAL_ATTRIB_LEGACY = "phoenix.queryserver.kerberos.http.principal";
+    public static final String QUERY_SERVER_KERBEROS_HTTP_PRINCIPAL_ATTRIB = "phoenix.queryserver.http.kerberos.principal";
     public static final String QUERY_SERVER_DNS_NAMESERVER_ATTRIB = "phoenix.queryserver.dns.nameserver";
     public static final String QUERY_SERVER_DNS_INTERFACE_ATTRIB = "phoenix.queryserver.dns.interface";
     public static final String QUERY_SERVER_HBASE_SECURITY_CONF_ATTRIB = "hbase.security.authentication";