commit can't mkdir on an existing file

[ezrizhu]

try/try

Line 129 in adc117d

mkdir "${local_file}"

Above line fails if directory already exists

touch x
echo 'rm x; mkdir x; touch x/y' > test.sh
./try bash test.sh
mkdir: cannot create directory ‘/home/ubuntu/trymkdir/x’: File exists
couldn't commit /tmp/tmp.qT6BjMKMLb/upperdir/home/ubuntu/trymkdir/x

[mgree]

The correct solution here is to delete x before calling mkdir when committing. We should change the summary to highlight this (i.e., the change is "delete x and then create all this other stuff").