Include the upstream toybox version in "toybox --version".

SHAs have their uses, but upstream version numbers are better for getting
a quick ballpark figure for the version.

Before:
  afc66714a4e3-android

After:
  0.7.0-afc66714a4e3-android

Change-Id: Id546ddd003bed995043719bd6e8c7b6c42cb498f
1 file changed