Fixes wp-cli#312.

When uninstalling a network activated plugin, the network tag is now added to correctly deactivate the plugin before removal.

src/Plugin_Command.php

@@ -924,7 +924,11 @@ public function uninstall( $args, $assoc_args = array() ) {
 			if ( Utils\get_flag_value( $assoc_args, 'deactivate' ) ) {
 				WP_CLI::log( "Deactivating '{$plugin->name}'..." );
 				$this->chained_command = true;
-				$this->deactivate( array( $plugin->name ) );
+				$args                  = [];
+				if ( is_plugin_active_for_network( $plugin->file ) ) {
+					$args['network'] = true;
+				}
+				$this->deactivate( array( $plugin->name ), $args );
 				$this->chained_command = false;
 			}