net: better debugging for network state changes
net: Do not automatically disconnect upon network session failure

These messages were sometimes produced even on the desktop version
(unfortunately, I don't know details, just that it happened once for me). The
real problem was, as usual, on Harmattan -- the error message was emitted upon
each AP change, which was rather noisy. Better kill it altogether, the generic
code in onGlobalOnlineStateChanged() shall catch the disconnects, so they will
work well.

REVIEW: 115151