Update installation.rst
Update installation.rst

Adds a couple of installation steps to:
init datasources
modify /etc/hosts
build the c extensions
wlach/treeherder,akhileshpillai/treeherder,gbrmachado/treeherder,jgraham/treeherder,gbrmachado/treeherder,kapy2010/treeherder,KWierso/treeherder,avih/treeherder,gbrmachado/treeherder,tojon/treeherder,rail/treeherder,adusca/treeherder,sylvestre/treeherder,jgraham/treeherder,glenn124f/treeherder,tojonmz/treeherder,deathping1994/treeherder,adusca/treeherder,tojon/treeherder,parkouss/treeherder,parkouss/treeherder,vaishalitekale/treeherder,glenn124f/treeherder,rail/treeherder,deathping1994/treeherder,vaishalitekale/treeherder,tojonmz/treeherder,akhileshpillai/treeherder,vaishalitekale/treeherder,rail/treeherder,avih/treeherder,vaishalitekale/treeherder,tojonmz/treeherder,tojon/treeherder,KWierso/treeherder,moijes12/treeherder,sylvestre/treeherder,moijes12/treeherder,kapy2010/treeherder,rail/treeherder,edmorley/treeherder,gbrmachado/treeherder,tojonmz/treeherder,kapy2010/treeherder,jgraham/treeherder,moijes12/treeherder,wlach/treeherder,vaishalitekale/treeherder,akhileshpillai/treeherder,avih/treeherder,rail/treeherder,wlach/treeherder,kapy2010/treeherder,wlach/treeherder,akhileshpillai/treeherder,wlach/treeherder,edmorley/treeherder,adusca/treeherder,deathping1994/treeherder,jgraham/treeherder,KWierso/treeherder,parkouss/treeherder,adusca/treeherder,akhileshpillai/treeherder,glenn124f/treeherder,gbrmachado/treeherder,parkouss/treeherder,moijes12/treeherder,glenn124f/treeherder,avih/treeherder,avih/treeherder,jgraham/treeherder,akhileshpillai/treeherder,parkouss/treeherder,tojonmz/treeherder,adusca/treeherder,jgraham/treeherder,rail/treeherder,edmorley/treeherder,glenn124f/treeherder,moijes12/treeherder,sylvestre/treeherder,glenn124f/treeherder,wlach/treeherder,deathping1994/treeherder,vaishalitekale/treeherder,moijes12/treeherder,tojonmz/treeherder,sylvestre/treeherder,gbrmachado/treeherder,avih/treeherder,adusca/treeherder,kapy2010/treeherder,KWierso/treeherder,tojon/treeherder,deathping1994/treeherder,edmorley/treeherder,sylvestre/treeherder,parkouss/treeherder,deathping1994/treeherder,sylvestre/treeherder