Fix RepositoryConfig.setStringList to not corrupt internal state
Calling setStringList was incorrectly storing the String objects
directly in byName. The byName table should have either an Entry or
a List<Entry> stored within its value position. Storing the String
(or List<String>) directly confused our get code as it did not find
the object type it expected. This caused the get code to fallback
to the base configuration (e.g. ~/.gitconfig) or just return null
(claiming the value was never set).
A test case for this appears in the next commit.
Noticed-by: Marek Zawirski <marek.zawirski@gmail.com>
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>