Fix ripping discs with less than ten tracks

Output lines of cdrdao for single digit track numbers with a
whitespace character.

Broken since whipper-team#345 was merged.

Signed-off-by: Andreas Oberritter <obi@saftware.de>

whipper/program/cdrdao.py

@@ -19,7 +19,7 @@
 _CRC_RE = re.compile(
     r"Found (?P<channels>[0-9]*) Q sub-channels with CRC errors")
 _BEGIN_CDRDAO_RE = re.compile(r"-" * 60)
-_LAST_TRACK_RE = re.compile(r"^(?P<track>[0-9]*)")
+_LAST_TRACK_RE = re.compile(r"^[ ]?(?P<track>[0-9]*)")
 _LEADOUT_RE = re.compile(
     r"^Leadout AUDIO\s*[0-9]\s*[0-9]*:[0-9]*:[0-9]*\([0-9]*\)")