Do not append to default values in {String,Int}Slice

I added the ability to do: `-s=bob -s=john` and get `[]string{"bob", "john"}`

But if a default value was set to say `[]string{"eric"}` the above
operation was mistakenly resulting in: `[]string{"eric", "bob", "john"}
which was obviously not what was intended.

This is fixed by tracking if a value was parsed and overwriting the
default on the first time -s is found, but we append the 2+ time.

0 files changed, 0 insertions, 0 deletions