Merge branch 'version/2.2' into version/2.3

* version/2.2:
  Set an empty string to avoid a warning
  Updated the installation instructions

docs/install.html

@@ -56,7 +56,7 @@ To download the repository, move to a suitable directory and run the following o
 command line:
 </p>
 <pre>
-        git clone https://github.com/Ensembl/ensembl-hive.git
+        git clone -b version/2.3 https://github.com/Ensembl/ensembl-hive.git
 </pre>
 
 <p>