devtools: fix x86-default build test install env
devtools: fix x86-default build test install env

The x86-default environment was loaded after installing this target.
I did not see any problem with it, yet we should load corresponding
environment before installing a target.

Fixes: bd253daa7717 ("devtools: fix test of ninja install")
Cc: stable@dpdk.org

Signed-off-by: David Marchand <f28529695cfa9e3e1eb84e7072aa626af4abb18e@redhat.com>

john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk