Qbs: Allow for tweaking of Qbs log level via environment
Qbs: Allow for tweaking of Qbs log level via environment

Set QBS_LOG_LEVEL to any number, the higher the more messages you
will get.

Change-Id: I6ae0d3a5bb94ad6865cd57d9ff381d36c8c8e95e
Reviewed-by: Tobias Hunger <012f8d714267bccc9d4766fbeace9f175fcc70c4@digia.com>

kuba1/qtcreator,maui-packages/qt-creator,danimo/qt-creator,maui-packages/qt-creator,omniacreator/qtcreator,richardmg/qtcreator,maui-packages/qt-creator,omniacreator/qtcreator,xianian/qt-creator,Distrotech/qtcreator,xianian/qt-creator,amyvmiwei/qt-creator,duythanhphan/qt-creator,darksylinc/qt-creator,darksylinc/qt-creator,farseerri/git_code,duythanhphan/qt-creator,AltarBeastiful/qt-creator,richardmg/qtcreator,martyone/sailfish-qtcreator,AltarBeastiful/qt-creator,danimo/qt-creator,AltarBeastiful/qt-creator,Distrotech/qtcreator,malikcjm/qtcreator,colede/qtcreator,richardmg/qtcreator,richardmg/qtcreator,danimo/qt-creator,xianian/qt-creator,malikcjm/qtcreator,omniacreator/qtcreator,AltarBeastiful/qt-creator,duythanhphan/qt-creator,martyone/sailfish-qtcreator,malikcjm/qtcreator,maui-packages/qt-creator,colede/qtcreator,danimo/qt-creator,darksylinc/qt-creator,farseerri/git_code,kuba1/qtcreator,malikcjm/qtcreator,colede/qtcreator,AltarBeastiful/qt-creator,martyone/sailfish-qtcreator,malikcjm/qtcreator,darksylinc/qt-creator,duythanhphan/qt-creator,kuba1/qtcreator,AltarBeastiful/qt-creator,richardmg/qtcreator,kuba1/qtcreator,xianian/qt-creator,colede/qtcreator,xianian/qt-creator,xianian/qt-creator,colede/qtcreator,farseerri/git_code,duythanhphan/qt-creator,farseerri/git_code,martyone/sailfish-qtcreator,amyvmiwei/qt-creator,darksylinc/qt-creator,Distrotech/qtcreator,xianian/qt-creator,duythanhphan/qt-creator,danimo/qt-creator,maui-packages/qt-creator,farseerri/git_code,kuba1/qtcreator,omniacreator/qtcreator,kuba1/qtcreator,colede/qtcreator,maui-packages/qt-creator,danimo/qt-creator,farseerri/git_code,farseerri/git_code,amyvmiwei/qt-creator,richardmg/qtcreator,danimo/qt-creator,xianian/qt-creator,martyone/sailfish-qtcreator,martyone/sailfish-qtcreator,amyvmiwei/qt-creator,Distrotech/qtcreator,martyone/sailfish-qtcreator,malikcjm/qtcreator,amyvmiwei/qt-creator,amyvmiwei/qt-creator,AltarBeastiful/qt-creator,colede/qtcreator,danimo/qt-creator,duythanhphan/qt-creator,danimo/qt-creator,amyvmiwei/qt-creator,amyvmiwei/qt-creator,kuba1/qtcreator,martyone/sailfish-qtcreator,richardmg/qtcreator,kuba1/qtcreator,martyone/sailfish-qtcreator,Distrotech/qtcreator,darksylinc/qt-creator,kuba1/qtcreator,omniacreator/qtcreator,omniacreator/qtcreator,AltarBeastiful/qt-creator,Distrotech/qtcreator,Distrotech/qtcreator,omniacreator/qtcreator,xianian/qt-creator,darksylinc/qt-creator,malikcjm/qtcreator,darksylinc/qt-creator,farseerri/git_code,maui-packages/qt-creator