TBR: v.io/jiri/profiles: FindTarget == FindTargetWithDefault

Before this CL, FindTarget == FindTargetWithDefault, which seems
incorrect.  In particular, it was causing:

EnsureProfileTargetIsInstalled(..., "amd64-linux")

to succeed, even though the "arm-android" profile was installed.

Change-Id: I01896acffaa4b23d2b91892061079412bb9e075e
2 files changed