exit instead of return if sideload file creation fails

A return here leaves adb sideload in a permanent loop. An exit is
more appropriate for this error.

Change-Id: I80fb8abae4f6378833aa75f9eaf7ec1acd44b274
Signed-off-by: Ethan Yonker <ethanayonker@gmail.com>
diff --git a/minadbd/services.c b/minadbd/services.c
index aef37f7..6b5e3b9 100644
--- a/minadbd/services.c
+++ b/minadbd/services.c
@@ -55,7 +55,7 @@
     if(fd < 0) {
         fprintf(stderr, "failed to create %s\n", ADB_SIDELOAD_FILENAME);
         adb_close(s);
-        return;
+        exit(1);
     }
 
     while(count > 0) {