This moves the error variables that had been moved to the
internal/common package during recent refactoring to a non-internal
errors package, once again allowing consumers to test for particular
error conditions.
To preserve API compatibility with bbolt v1.3, these error variables
are also redefined in the bbolt package, with deprecation notice to
migrate to bbolt/errors.
Signed-off-by: Josh Rickmar <jrick@zettaport.com>
Josh Rickmar