Cache develop DITA-OT using ETag as cache key
Cache develop DITA-OT using ETag as cache key

Signed-off-by: Jarno Elovirta <0f1ab0ac7dffd9db21aa539af2fd4bb04abc3ad4@elovirta.com>

infotexture/docs,infotexture/docs,dita-ot/docs