Make version processing handle w.x.y.z versions.

Ubuntu 12.04.1 uses gnome-terminal 3.4.1.1; the previous regex (without the
space before the capturing parenthesis) captured 4.1.1, so the version check
set newGnome=1 and installation failed.  This change fixes the regex.

Also simplify the command, removing the unnecessary echo and backticks.