Don't reopen already opened wallet.
Don't reopen already opened wallet.

* subversion/libsvn_auth_kwallet/kwallet.cpp
  (wallet): New.
  (kwallet_password_get, kwallet_password_set): Open wallet only when wallet
   wasn't opened earlier.
  (kwallet_disconnect): New.


git-svn-id: f8a4e5e023278da1e04e203c7fe051e3c4285d88@874204 13f79535-47bb-0310-9956-ffa450edef68

YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,wbond/subversion,wbond/subversion,wbond/subversion,YueLinHo/Subversion,wbond/subversion,wbond/subversion,wbond/subversion,wbond/subversion,YueLinHo/Subversion,YueLinHo/Subversion