1440837 bug fix and ssh error catching
1440837 bug fix and ssh error catching

Testing sudo access on all nodes.

Added error checking to make sure all nodes entered are valid.

Edit 1: Small change to error checking

Change-Id: Ife2c6ec9769be94b9f26a9c94fef74c9c1b43d56

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