test-install: Avoid hardcoded paths in /tmp.
test-install: Avoid hardcoded paths in /tmp.

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

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