[sql] do not switch to the DB view if only the log_line column is selected
[sql] do not switch to the DB view if only the log_line column is selected

Fixes #78

acleasby/lnav,tstack/lnav,acleasby/lnav,sureshsundriyal/lnav,acleasby/lnav,acleasby/lnav,sureshsundriyal/lnav,acleasby/lnav,sureshsundriyal/lnav,tstack/lnav,sureshsundriyal/lnav,tstack/lnav,tstack/lnav