EHN:Use find_package(Git) only with CMake >=2.8.2
EHN:Use find_package(Git) only with CMake >=2.8.2

Otherwise fackback to use find_program directly because FindGit.cmake did
not exist prior to CMake 2.8.2

Change-Id: Ifef68d110a2d21b73674550e7057075a7a4de1a2

OSEHRA/VistA,mdgeek/VistA-FHIR-CWF,shabiel/VistA,OSEHRA-Sandbox/VistA,timmvt/VistA_tt,OSEHRA/VistA,timmvt/VistA_tt,timmvt/VistA_tt,jasonli2000/VistA,mdgeek/VistA-FHIR-CWF,shabiel/VistA,mdgeek/VistA-FHIR-CWF,OSEHRA/VistA,josephsnyder/VistA,OSEHRA-Sandbox/VistA,josephsnyder/VistA,shabiel/VistA,mdgeek/VistA-FHIR-CWF,apexdatasolutions/VistA,timmvt/VistA_tt,josephsnyder/VistA,apexdatasolutions/VistA,jasonli2000/VistA,josephsnyder/VistA,apexdatasolutions/VistA,OSEHRA/VistA,jasonli2000/VistA,OSEHRA/VistA,josephsnyder/VistA,OSEHRA-Sandbox/VistA,shabiel/VistA,shabiel/VistA,shabiel/VistA,mdgeek/VistA-FHIR-CWF,jasonli2000/VistA,josephsnyder/VistA,OSEHRA-Sandbox/VistA,mdgeek/VistA-FHIR-CWF,apexdatasolutions/VistA,OSEHRA/VistA,OSEHRA-Sandbox/VistA,OSEHRA-Sandbox/VistA,timmvt/VistA_tt,apexdatasolutions/VistA