Fix xlog/upgrade.test.lua after bad merge

Closes #2934

test/xlog/suite.cfg

 {
     "upgrade.test.lua": {
-        "1.6.5": {"version": "1.6.5"},
-        "1.6.6": {"version": "1.6.6"},
-        "1.6.7": {"version": "1.6.7"},
-        "1.6.8": {"version": "1.6.8"},
-        "1.6.9": {"version": "1.6.9"},
-        "1.7.2": {"version": "1.7.2"},
         "1.7.5": {"version": "1.7.5"},
         "1.7.6": {"version": "1.7.6"}
     }