message: adapt legitimate cargo install usage to avoid the new warning/error
diff: @@ -742,7 +742,7 @@ fn install_default_features() {
  .file("examples/foo.rs", "fn main() {}")
  .build();
  - assert_that(p.cargo("install"), execs().with_status(0));
  + assert_that(p.cargo("install --path ."), execs().with_status(0));
  assert_that(cargo_home(), has_installed_exe("foo"));
  assert_that(p.cargo("uninstall").arg("foo"), execs().with_status(0));
  @@ -868,7 +868,7 @@ fn install_multiple_required_features() {
  .file("src/foo_2.rs", "fn main() {}")
  .build();
  - assert_that(p.cargo("install"), execs().with_status(0));
  + assert_that(p.cargo("install --path ."), execs().with_status(0));
  assert_that(cargo_home(), is_not(has_installed_exe("foo_1")));
  assert_that(cargo_home(), has_installed_exe("foo_2"));
  assert_that(p.cargo("uninstall").arg("foo"), execs().with_status(0));
  @@ -1166,7 +1166,7 @@ Consider enabling them by passing e.g. `--features=\"bar/a\"`
  // install
  assert_that(
  - p.cargo("install"),
  + p.cargo("install --path ."),
  execs().with_status(101).with_stderr(format!(
  "\
  [INSTALLING] foo v0.0.1 ([..])
  