Docs: Added note about RPMs not being supported on SLES 11

docs/reference/setup/install/rpm.asciidoc

@@ -6,6 +6,9 @@ or from our  <<rpm-repo,RPM repository>>. It can be used to install
 Elasticsearch on any RPM-based system such as OpenSuSE, SLES, Centos, Red Hat,
 and Oracle Enterprise.
 
+NOTE: RPM install is not supported on SLES 11.  Please see <<zip-targz>>
+instead.
+
 The latest stable version of Elasticsearch can be found on the
 link:/downloads/elasticsearch[Download Elasticsearch] page. Other versions can
 be found on the link:/downloads/past-releases[Past Releases page].
@@ -20,14 +23,6 @@ include::key.asciidoc[]
 rpm --import https://packages.elastic.co/GPG-KEY-elasticsearch
 -------------------------
 
-If using an older version of RPM, you may need to do this in two steps:
-
-[source,sh]
--------------------------
-curl https://packages.elastic.co/GPG-KEY-elasticsearch > elasticsearch.asc
-rpm --import elasticsearch.asc
--------------------------
-
 [[rpm-repo]]
 ==== Installing from the RPM repository