fetchgit does not use --depth=1

[Atemu]

For some reason, fetchgit does not use --depth=1 anymore as if deepClone was true. This is extremely noticeable in android_frameworks_base which is multiple gigabytes in size and takes forever to fetch.

Using --depth=1 isn't fast by any means but still multiple times faster.

cc @eyJhb since you last touched fetchgit related things