SSH: Close unused cached connections after a period of inactivity.
SSH: Close unused cached connections after a period of inactivity.

We keep connections open to avoid re-doing the authentication procedure
when the user runs or deploys a remote app repeatedly.
However, the connections should not be around indefinitely; we therefore
now close them after about five minutes of inactivity.

Change-Id: Ie677eb133b618d34c08528da2f2bc221472316b3
Reviewed-by: hjk <f81b91af79013637d070c18d38a75b90eaae8ba3@nokiamail.com>
Reviewed-by: Christian Kandeler <3aa99dcdd3f0cac61fb81c2a11771c0cc2497607@theqtcompany.com>

martyone/sailfish-qtcreator,kuba1/qtcreator,martyone/sailfish-qtcreator,amyvmiwei/qt-creator,kuba1/qtcreator,xianian/qt-creator,danimo/qt-creator,xianian/qt-creator,AltarBeastiful/qt-creator,farseerri/git_code,amyvmiwei/qt-creator,farseerri/git_code,danimo/qt-creator,farseerri/git_code,martyone/sailfish-qtcreator,farseerri/git_code,Distrotech/qtcreator,Distrotech/qtcreator,martyone/sailfish-qtcreator,xianian/qt-creator,farseerri/git_code,AltarBeastiful/qt-creator,kuba1/qtcreator,xianian/qt-creator,kuba1/qtcreator,kuba1/qtcreator,martyone/sailfish-qtcreator,Distrotech/qtcreator,danimo/qt-creator,amyvmiwei/qt-creator,kuba1/qtcreator,Distrotech/qtcreator,martyone/sailfish-qtcreator,farseerri/git_code,AltarBeastiful/qt-creator,danimo/qt-creator,AltarBeastiful/qt-creator,xianian/qt-creator,AltarBeastiful/qt-creator,amyvmiwei/qt-creator,amyvmiwei/qt-creator,Distrotech/qtcreator,amyvmiwei/qt-creator,martyone/sailfish-qtcreator,martyone/sailfish-qtcreator,AltarBeastiful/qt-creator,danimo/qt-creator,farseerri/git_code,danimo/qt-creator,danimo/qt-creator,amyvmiwei/qt-creator,kuba1/qtcreator,AltarBeastiful/qt-creator,xianian/qt-creator,amyvmiwei/qt-creator,xianian/qt-creator,danimo/qt-creator,farseerri/git_code,xianian/qt-creator,Distrotech/qtcreator,AltarBeastiful/qt-creator,Distrotech/qtcreator,xianian/qt-creator,kuba1/qtcreator,kuba1/qtcreator,danimo/qt-creator,martyone/sailfish-qtcreator