Tests fail when /tmp is mounted with noeexec option

[vojtechsokol]

git clone https://github.com/leapp-to/leapp-go
cd leapp-go
make test
?       _/root/leapp-go/cmd/actor-stdout        [no test files]
fork/exec /tmp/go-build232987098/_/root/leapp-go/cmd/leapp-daemon/_test/leapp-daemon.test: permission denied
FAIL    _/root/leapp-go/cmd/leapp-daemon        0.009s
fork/exec /tmp/go-build232987098/_/root/leapp-go/pkg/api/_test/api.test: permission denied
FAIL    _/root/leapp-go/pkg/api 0.000s
fork/exec /tmp/go-build232987098/_/root/leapp-go/pkg/db/_test/db.test: permission denied
FAIL    _/root/leapp-go/pkg/db  0.002s
fork/exec /tmp/go-build232987098/_/root/leapp-go/pkg/executor/_test/executor.test: permission denied
FAIL    _/root/leapp-go/pkg/executor    0.000s
?       _/root/leapp-go/pkg/web [no test files]
make: *** [Makefile:25: test] Error 1

The permision denied error is caused by mounting /tmp with noexec option (in docker container):

findmnt /tmp
/tmp   tmpfs  tmpfs  rw,nosuid,nodev,noexec,relatime,seclabel

A possible workaround is to set TMPDIR environment variable:

TMPDIR=/root/go-tmp/ make test
?       _/root/leapp-go/cmd/actor-stdout        [no test files]
ok      _/root/leapp-go/cmd/leapp-daemon        0.026s                                                                                                                                                                                       
ok      _/root/leapp-go/pkg/api 0.003s                                                                                                                                                                                                       
ok      _/root/leapp-go/pkg/db  0.002s                                                                                                                                                                                                       
ok      _/root/leapp-go/pkg/executor    0.010s                                                                                                                                                                                               
?       _/root/leapp-go/pkg/web [no test files]    

Other way is to use Go 1.10, where GOTMPDIR can be specified.