treestore: changes for golint
treestore: changes for golint

(the couple of changes to non-exported varialbes/functions were because
they were not found to be used anywhere.)

Signed-off-by: Vincent Batts <d01a4772f0cffd3f005a7d7f01c59cd104c7a5fe@hashbangbash.com>

joshix/rkt,joshix/rkt,joshix/rkt,kinvolk/rkt,Shashwatsh/rkt,joshix/rkt,rkt/rkt,coreos/rkt,intelsdi-x/rkt,kinvolk/rkt,ybubnov/rkt,coreos/rkt,sstabellini/rkt,rkt/rkt,lucasallan/rkt,Shashwatsh/rkt,ybubnov/rkt,coreos/rkt,lucasallan/rkt,intelsdi-x/rkt,lucasallan/rkt,intelsdi-x/rkt,kinvolk/rkt,alban/rkt,sstabellini/rkt,kinvolk/rkt,lucasallan/rkt,rkt/rkt,alban/rkt,sstabellini/rkt,ybubnov/rkt,Shashwatsh/rkt,alban/rkt,rkt/rkt