tracking DQM: FractionOfGoodTracks back to standard distribution

previous pull request (https://github.com/cms-sw/cmssw/pull/2034) has been used as default

in previous commit the definition of the fraction of good tracks changed
this commit is therefore aimed to have back the standard definition

2 new parameters have been added
- numSelection
- denSelection

they are StringCutObjectSelectors and they are used in order to specify the proper track selections which have to be applied on the numerator and denominator of the considered, respectively

the configuration file for proton collision jobs has been updated as well