[TxMt] [TM2] TM forgets closed file browser's current directory on restart

[John Whitley]

TM2 bug report; I haven't seen this one go by yet.

Repro steps:
1) Open a TM2 window on a directory, e.g. via 'mate somedir'
   The file browser should be open at that directory
2) Open a second window on another directory, e.g. via 'mate somedir2'
3) Open a few files in each window for good measure
4) Close the file browser pane in the first ('somedir') window,
   via View -> Hide File Browser or shortcut
5) Exit TextMate
6) Start TextMate
7) Observe: TM2 reopens windows that were present when it last exited.
8) Open file browser in the first window (aka 'somedir')

Expected result:
The file browser for the window with files from 'somedir' should retain its
state from the prior session, opening to 'somedir' or the last directory it was
viewing.

Actual result:
The file browser in question opens to the user's home directory.