Increase window SF and chi2Cut_min to recover hits

[mmasciov]

PR description:

This PR acts on top of PR #385 and increases the flat SF applied to hit selection windows, in order to recover hits. With the same goal, the min chi2 cut is explicitly increased to 15.0.

PR validation:

• TTbar with =50: https://mmasciovecchio.web.cern.ch/MkFit_hitSelectionWindows_Nov21/MTV_fixHitSelWindows_minChi215p0_SF1p1_Nov21_TTbarPU50_122X/
• 10muPt0p2to10: https://mmasciovecchio.web.cern.ch/MkFit_hitSelectionWindows_Nov21/MTV_fixHitSelWindows_minChi215p0_SF1p1_Nov21_10muPt0p2to10_122X/

--> A slight increase in fakes is found, in exchange for an increase in number of hits (and a slight improvement in resolutions, especially pT resolution).

[slava77]

A slight increase in fakes is found, in exchange for an increase in number of hits (and a slight improvement in resolutions, especially pT resolution).

the fake rate increase was not that visible (based on the skype discussion yesterday)