Prevent to add files to list more than once

For special case:
1. It is the first commit(initialized repository)
2. More then one file are added to index.
3. User picks more than one file, and right click on them to commit
   (the variable *list* is not point to NULL.)
   (the value of *count* used by for-loop is more then 1.)

The for-loop is used for checking each file.
But, it should not check each file any more for initialized repository
since 0e010a554460fd36a4b681ea044b53d6c9fc2dfc
amd b091e999654efb9872273de11c0530b71e600e01.

Therefor, all added files have been listed, it done there.
Don't go next iteration in that loop by adding "break".

Signed-off-by: Yue Lin Ho <b8732003@student.nsysu.edu.tw>