fix(doctor): fix error handling in setup checks

closes #174

Author: acburdine

lib/commands/doctor/checks/setup.js

@@ -36,26 +36,28 @@ module.exports = [{
                 })
             }], {concurrent: true, renderer: context.verbose ? context.renderer : 'silent', exitOnError: false})
                 .run(context).catch(() => {
-                    let errors = [];
+                    let missing = [];
 
                     if (!context.systemd) {
-                        errors.push('systemd');
+                        missing.push('systemd');
                     }
 
                     if (!context.nginx) {
-                        errors.push('nginx');
+                        missing.push('nginx');
                     }
 
-                    if (errors.length) {
-                        return Promise.reject(new errors.SystemError(chalk.yellow(`Missing package(s): ${errors.join(', ')}`)));
+                    if (missing.length) {
+                        return Promise.reject(new errors.SystemError(chalk.yellow(`Missing package(s): ${missing.join(', ')}`)));
                     }
                 });
         }).catch((error) => {
             // If the error caught is not a SystemError, something went wrong with execa,
             // so throw a ProcessError instead
             if (!(error instanceof errors.SystemError)) {
-                return Promise.reject(new errors.ProcessError(error));
+                error = new errors.ProcessError(error);
             }
+
+            return Promise.reject(error);
         });
     }
 }];