Log on boot errors with one role

We didn't log boot errors if there was one role because there was no
barrier and the logging is done by the first host to close the barrier.

Let's always create the barrier to fix this.

lib/kamal/cli/app.rb

@@ -14,7 +14,7 @@ class Kamal::Cli::App < Kamal::Cli::Base
         end
 
         # Primary hosts and roles are returned first, so they can open the barrier
-        barrier = Kamal::Cli::Healthcheck::Barrier.new if KAMAL.roles.many?
+        barrier = Kamal::Cli::Healthcheck::Barrier.new
 
         on(KAMAL.hosts, **KAMAL.boot_strategy) do |host|
           KAMAL.roles_on(host).each do |role|

lib/kamal/cli/app/boot.rb

@@ -72,7 +72,7 @@ class Kamal::Cli::App::Boot
 
     def release_barrier
       if barrier.open
-        info "First #{KAMAL.primary_role} container is healthy on #{host}, booting other roles"
+        info "First #{KAMAL.primary_role} container is healthy on #{host}, booting any other roles"
       end
     end
 
@@ -87,7 +87,7 @@ class Kamal::Cli::App::Boot
 
     def close_barrier
       if barrier.close
-        info "First #{KAMAL.primary_role} container is unhealthy on #{host}, not booting other roles"
+        info "First #{KAMAL.primary_role} container is unhealthy on #{host}, not booting any other roles"
         error capture_with_info(*app.logs(version: version))
         error capture_with_info(*app.container_health_log(version: version))
       end