builtin-apply: minor cleanup of whitespace detection
builtin-apply: minor cleanup of whitespace detection

Use 0 instead of -1 for the case where not tabs or spaces are found; it
will make some later math slightly simpler.

Signed-off-by: J. Bruce Fields <51738506c1b2ccb0761f23bdc612c93babf738ea@citi.umich.edu>
Signed-off-by: Junio C Hamano <a6723cc3f76163bf7adb636a73ac3b0ceb3e6b9b@pobox.com>

destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git