Fix potential KeyError with 'lines_added' in 55e46db.

[hoxu@users.sf.net: rewrote commit message]

Signed-off-by: Heikki Hokkanen <hoxu@users.sf.net>

gitstats

@@ -246,7 +246,7 @@ class GitDataCollector(DataCollector):
 
 		# Collect revision statistics
 		# Outputs "<stamp> <date> <time> <timezone> <author> '<' <mail> '>'"
-		lines = getpipeoutput(['git rev-list --pretty=format:"%%at %%ai %%an <%%aE>" %s' % getcommitrange('HEAD'), 'grep -v ^commit']).split('\n')
+		lines = getpipeoutput(['git rev-list --pretty=format:"%%at %%ai %%aN <%%aE>" %s' % getcommitrange('HEAD'), 'grep -v ^commit']).split('\n')
 		for line in lines:
 			parts = line.split(' ', 4)
 			author = ''