lsif-server: create /lsif-storage as privileged user
Created by: ggilmore
Currently CI is failing with this error:
_bk;t=1585165949499#24 digest: sha256:6e00cdda7d458254ba56e7c6ac5f53954ec7020f2deac521ccd49cdc05fe1b80
_bk;t=1585165949499#24 name: "[stage-2 9/9] RUN mkdir -p /lsif-storage && chown -R sourcegraph:sourcegraph /lsif-storage"
_bk;t=1585165949499#24 started: 2020-03-25 19:52:29.498160232 +0000 UTC
_bk;t=1585165949499#24 0.889 mkdir: can't create directory '/lsif-storage': Permission denied
_bk;t=1585165950426#24 completed: 2020-03-25 19:52:30.507564455 +0000 UTC
_bk;t=1585165950508#24 duration: 1.009404223s
_bk;t=1585165950508#24 error: "executor failed running [/bin/sh -c mkdir -p /lsif-storage && chown -R sourcegraph:sourcegraph /lsif-storage]: exit code: 1"
_bk;t=1585165950508
_bk;t=1585165950508executor failed running [/bin/sh -c mkdir -p /lsif-storage && chown -R sourcegraph:sourcegraph /lsif-storage]: exit code: 1