Don't re-add galaxy deps if they've already been added for install

Fixes #8890

bin/ansible-galaxy

@@ -780,7 +780,7 @@ def execute_install(args, options, parser):
             # we're done with the temp file, clean it up
             os.unlink(tmp_file)
             # install dependencies, if we want them
-            if not no_deps:
+            if not no_deps and installed:
                 if not role_data:
                     role_data = get_role_metadata(role.get("name"), options)
                     role_dependencies = role_data['dependencies']
@@ -792,12 +792,15 @@ def execute_install(args, options, parser):
                     else:
                         dep = ansible.utils.role_yaml_parse(dep)
                     if not get_role_metadata(dep["name"], options):
-                        print '- adding dependency: %s' % dep["name"]
-                        roles_left.append(dep)
+                        if dep not in roles_left:
+                            print '- adding dependency: %s' % dep["name"]
+                            roles_left.append(dep)
+                        else:
+                            print '- dependency %s already pending installation.' % dep["name"]
                     else:
                         print '- dependency %s is already installed, skipping.' % dep["name"]
         if not tmp_file or not installed:
-            if tmp_file:
+            if tmp_file and installed:
                 os.unlink(tmp_file)
             print "- %s was NOT installed successfully." % role.get("name")
             exit_without_ignore(options)