Increment API 23 samples version (DO NOT MERGE)

Sample release: 2015-11
New package version: 4

Change-Id: I40b2a3e33d1db2d147e15be73a488d597e761d4a

Author: tjohns

samples/samples_source.prop_template

@@ -1,4 +1,4 @@
 Pkg.UserSrc=false
-Pkg.Revision=3
+Pkg.Revision=4
 AndroidVersion.ApiLevel=${PLATFORM_SDK_VERSION}
 AndroidVersion.CodeName=${PLATFORM_VERSION_CODENAME}