gnucash maint: Use python 3.3 VirtualEnv on travis.

[John Ralls]

Updated	 via  https://github.com/Gnucash/gnucash/commit/aa2c1303 (commit)
	from  https://github.com/Gnucash/gnucash/commit/ed8e79c6 (commit)



commit aa2c1303fd642cf5f8de74e2c48e9a68279a7a20
Author: John Ralls <jralls at ceridwen.us>
Date:   Sat Jan 23 10:45:36 2016 -0800

    Use python 3.3 VirtualEnv on travis.
    
    Should fix get-pip.py installation failure.



Summary of changes:
 src/app-utils/gnc-sx-instance-model.c | 12 ++++++------
 src/gnome/dialog-sx-since-last-run.c  | 37 +++++++++++++++++++++++++++++++++--
 2 files changed, 41 insertions(+), 8 deletions(-)