Fix missing empty line in commit message during gitcc checkin

Fixes #44.
The empty line is missing while parsing git log and then commiting to CC.
Fix git log format to print raw body (%B).

checkin.py

@@ -9,7 +9,7 @@
 import cache, reset
 
 IGNORE_CONFLICTS=False
-LOG_FORMAT = '%H%x01%s%n%b'
+LOG_FORMAT = '%H%x01%B'
 CC_LABEL = ''
 
 ARGS = {