Added a 'make distclean' to step 2.8

2-IOC-deployment.md

@@ -181,7 +181,10 @@ $ echo "LINUX_NET_INSTALLED = NO" > configure/CONFIG_SITE.local
 
 ### 2.8 Build the IOC
 
+We do a clean build at this point to ensure the fix for the previous failed build takes effect.  The value that was set in in `CONFIG_SITE.local` causes some software to be exluded from the IOC.  Without the `make distclean` the excluded software can be partially included in the IOC, which results in build problems.
+
 ```
+$ make distclean
 $ make
 ```