gclient sync --revision src@$rev: fatal: remote error: upload-pack: not our ref

[Milan Hauth]

gclient sync applies the revision argument

to git submodules, so git throws

fatal: remote error: upload-pack: not our ref

reproduce:

rev=981fe92ab998d655abded58f1f0ef2a8daeadd02

git init

git fetch https://github.com/flutter/engine $rev

git checkout FETCH_HEAD

gclient config https://github.com/flutter/engine

#gclient sync --revision engine@$rev # good

gclient sync --revision src@$rev # bad

this is a user error, the revision argument should be

engine@${rev}

because "gclient config" creates .gconfig with

name = "engine"

but there is also a bug in "gclient sync":

the wrong revision spec is applied to *all* git submodules

so i get many error messages

fatal: remote error: upload-pack: not our ref 981fe92ab998d655abded58f1f0ef2a8daeadd02