优化返回值

app/src/main/java/com/xypower/mpapp/MicroPhotoService.java

@@ -1435,7 +1435,7 @@ public class MicroPhotoService extends Service {
 
         String[] params = new String[]{""};
         File workDir = context.getFilesDir();
-        int exitCode = 0;
+        int exitCode = -1;
 
         try {
             Process process = Runtime.getRuntime().exec(cmd, params, workDir.getAbsoluteFile());