repo: print a detailed error when version not found (#337)
repo: print a detailed error when version not found (#337)

Print a detailed error message for better debugging
when version specified is not found.

Signed-off-by: Naveen Kaje <79e427f88b1293e6ef90566b3bd0a85565336125@juul.com>
apache/incubator-mynewt-newt,apache/incubator-mynewt-newt