docs: update supported versions of Ubuntu

Change-Id: Ied9746692aabf26baa9a042912b85e99c6d1bf6b
diff --git a/docs/INSTALL.rst b/docs/INSTALL.rst
index cfee3fd..a4f422d 100644
--- a/docs/INSTALL.rst
+++ b/docs/INSTALL.rst
@@ -11,7 +11,7 @@
 
 -  Ubuntu 12.04 (64-bit and 32-bit)
 -  Ubuntu 14.04 (64-bit and 32-bit)
--  Ubuntu 14.10 (64-bit and 32-bit)
+-  Ubuntu 15.10 (64-bit)
 -  OS X 10.8
 -  OS X 10.9
 -  OS X 10.10