.travis.yml: Use /nonexistent instead of /tmp/nowhere.
.travis.yml: Use /nonexistent instead of /tmp/nowhere.

Signed-off-by: Anders Kaseorg <087231934ba8fcf78bc142ce37d193b895ac03c4@mit.edu>

hackerkid/zulip,kou/zulip,showell/zulip,showell/zulip,zulip/zulip,timabbott/zulip,eeshangarg/zulip,tommyip/zulip,brainwane/zulip,synicalsyntax/zulip,rishig/zulip,hackerkid/zulip,timabbott/zulip,eeshangarg/zulip,tommyip/zulip,synicalsyntax/zulip,brainwane/zulip,shubhamdhama/zulip,tommyip/zulip,timabbott/zulip,timabbott/zulip,eeshangarg/zulip,hackerkid/zulip,brainwane/zulip,brainwane/zulip,punchagan/zulip,showell/zulip,andersk/zulip,tommyip/zulip,showell/zulip,andersk/zulip,andersk/zulip,andersk/zulip,kou/zulip,shubhamdhama/zulip,shubhamdhama/zulip,shubhamdhama/zulip,zulip/zulip,timabbott/zulip,rht/zulip,timabbott/zulip,rht/zulip,zulip/zulip,tommyip/zulip,andersk/zulip,shubhamdhama/zulip,zulip/zulip,hackerkid/zulip,timabbott/zulip,kou/zulip,hackerkid/zulip,rht/zulip,showell/zulip,showell/zulip,brainwane/zulip,punchagan/zulip,synicalsyntax/zulip,rishig/zulip,punchagan/zulip,andersk/zulip,rht/zulip,zulip/zulip,brainwane/zulip,kou/zulip,eeshangarg/zulip,rishig/zulip,punchagan/zulip,eeshangarg/zulip,tommyip/zulip,synicalsyntax/zulip,rht/zulip,rishig/zulip,synicalsyntax/zulip,synicalsyntax/zulip,shubhamdhama/zulip,punchagan/zulip,rht/zulip,brainwane/zulip,punchagan/zulip,rishig/zulip,rht/zulip,hackerkid/zulip,zulip/zulip,rishig/zulip,showell/zulip,eeshangarg/zulip,synicalsyntax/zulip,shubhamdhama/zulip,kou/zulip,kou/zulip,kou/zulip,rishig/zulip,andersk/zulip,tommyip/zulip,punchagan/zulip,hackerkid/zulip,zulip/zulip,eeshangarg/zulip