Connect to the currentDirectoryChanged signal after the shell setup

This fixes the problem that the view URL may be reset to the Home URL
when opening the Terminal Panel while browsing a remote URL. Moreover,
it fixes crashes that can occur when the signal is received during the
shell setup if the DolphinMainWindow does not have a valid
m_activeViewContainer yet.

BUG: 339502
BUG: 340233
REVIEW: 120726
FIXED-IN: 4.14.3