Bug 1135798 - Deploy script: Fix the git fetch/reset commands
Bug 1135798 - Deploy script: Fix the git fetch/reset commands

The current fetch/reset/checkout doesn't correctly update the working
directory when switching between branches. This new approach is
recommended by:
http://stackoverflow.com/a/9589927

adusca/treeherder,kapy2010/treeherder,glenn124f/treeherder,sylvestre/treeherder,adusca/treeherder,tojon/treeherder,rail/treeherder,parkouss/treeherder,gbrmachado/treeherder,vaishalitekale/treeherder,adusca/treeherder,edmorley/treeherder,moijes12/treeherder,sylvestre/treeherder,deathping1994/treeherder,gbrmachado/treeherder,akhileshpillai/treeherder,wlach/treeherder,kapy2010/treeherder,jgraham/treeherder,moijes12/treeherder,adusca/treeherder,wlach/treeherder,gbrmachado/treeherder,gbrmachado/treeherder,KWierso/treeherder,sylvestre/treeherder,avih/treeherder,avih/treeherder,tojon/treeherder,tojonmz/treeherder,edmorley/treeherder,parkouss/treeherder,vaishalitekale/treeherder,moijes12/treeherder,glenn124f/treeherder,deathping1994/treeherder,vaishalitekale/treeherder,jgraham/treeherder,sylvestre/treeherder,deathping1994/treeherder,gbrmachado/treeherder,vaishalitekale/treeherder,rail/treeherder,vaishalitekale/treeherder,jgraham/treeherder,rail/treeherder,moijes12/treeherder,parkouss/treeherder,kapy2010/treeherder,tojon/treeherder,akhileshpillai/treeherder,jgraham/treeherder,KWierso/treeherder,vaishalitekale/treeherder,avih/treeherder,kapy2010/treeherder,wlach/treeherder,gbrmachado/treeherder,avih/treeherder,adusca/treeherder,tojon/treeherder,moijes12/treeherder,akhileshpillai/treeherder,edmorley/treeherder,rail/treeherder,tojonmz/treeherder,deathping1994/treeherder,tojonmz/treeherder,glenn124f/treeherder,KWierso/treeherder,parkouss/treeherder,rail/treeherder,tojonmz/treeherder,sylvestre/treeherder,glenn124f/treeherder,kapy2010/treeherder,parkouss/treeherder,avih/treeherder,avih/treeherder,deathping1994/treeherder,moijes12/treeherder,KWierso/treeherder,rail/treeherder,tojonmz/treeherder,glenn124f/treeherder,wlach/treeherder,wlach/treeherder,akhileshpillai/treeherder,deathping1994/treeherder,parkouss/treeherder,jgraham/treeherder,akhileshpillai/treeherder,akhileshpillai/treeherder,tojonmz/treeherder,wlach/treeherder,glenn124f/treeherder,sylvestre/treeherder,edmorley/treeherder,adusca/treeherder,jgraham/treeherder