Fix building on SmartOS
Fix building on SmartOS

SmartOS does not have the ext4 or brtfs bits needed.

Change-Id: Id29fd189a34fff6b8126c5715d091d200ba260db

couchbase/forestdb,hisundar/forestdb,zhaog/forestdb,wurikiji/forestdb,wurikiji/forestdb,zhaog/forestdb,jinxuan/forestdb,sushmaad/forestdb,joliss/forestdb,joliss/forestdb,couchbase/forestdb,sushmaad/forestdb,jinxuan/forestdb,hisundar/forestdb