Fix for bug 1443688
Fix for bug 1443688

Explain plan is now collected only for non-unique query types and queries that generate stats.

Also, fixed a bug where explain plan was being collected even though the
statistics feature is disabled.

Fixes bug 1443688

Change-Id: I67433083758044e1da0071241e00c4a09e701dbd

rlugojr/incubator-trafodion,mashengchen/incubator-trafodion,rlugojr/incubator-trafodion,rlugojr/incubator-trafodion,rlugojr/incubator-trafodion,mashengchen/incubator-trafodion,robertamarton/incubator-trafodion,mashengchen/incubator-trafodion,robertamarton/incubator-trafodion,robertamarton/incubator-trafodion,robertamarton/incubator-trafodion,mashengchen/incubator-trafodion,mashengchen/incubator-trafodion,rlugojr/incubator-trafodion,rlugojr/incubator-trafodion,rlugojr/incubator-trafodion,rlugojr/incubator-trafodion,mashengchen/incubator-trafodion,mashengchen/incubator-trafodion,robertamarton/incubator-trafodion,robertamarton/incubator-trafodion,mashengchen/incubator-trafodion,robertamarton/incubator-trafodion,rlugojr/incubator-trafodion,robertamarton/incubator-trafodion,mashengchen/incubator-trafodion,mashengchen/incubator-trafodion,rlugojr/incubator-trafodion,robertamarton/incubator-trafodion,robertamarton/incubator-trafodion