Use a different machine name for each time

This makes ITs more isolated and more robust

Signed-off-by: David Gageot <david@gageot.net>

test/integration/run-bats.sh

@@ -26,6 +26,8 @@ function machine() {
 
 function run_bats() {
     for bats_file in $(find "$1" -name \*.bats); do
+        export NAME="bats-$DRIVER-test-$(date +%s)"
+
         # BATS returns non-zero to indicate the tests have failed, we shouldn't
         # neccesarily bail in this case, so that's the reason for the e toggle.
         set +e
@@ -62,7 +64,6 @@ fi
 # TODO: Should the script bail out if these are set already?
 export BASE_TEST_DIR=$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )
 export MACHINE_ROOT="$BASE_TEST_DIR/../.."
-export NAME="bats-$DRIVER-test"
 export MACHINE_STORAGE_PATH="/tmp/machine-bats-test-$DRIVER"
 export MACHINE_BIN_NAME=docker-machine
 export BATS_LOG="$MACHINE_ROOT/bats.log"