Fix limit perPage in Eloquent simplePaginate function

[Farhan25]

Limit value should be the same as perPage, this small issue is not critical since the offset is right and limit is only 1 more than it should be, but it's right to fix if that's the case

This a scenario of the issue:
For example,
It retrieve first 11 records (1 --> 11) in page = 1 and perpage = 10 but it should retrieve only the first 10 (1 --> 10).
It retrieve 11 records (10 --> 21) in page = 2 and perpage = 10 but it should retrieve only the first 10 (10 --> 20).
Notice that row #11 is retrieved twice.

Notes:

1. The output is fine somehow, but I have discovered this issue when I used DB::enableQueryLog() and DB::getQueryLog().
2. This fix DOES another bug, causing the value of next_page_url to be null, I've tried to investigate it more but it seems that I lost in it.

[taylorotwell]

I am closing this pull request because it lacks sufficient explanation, tests, or both. It is difficult for us to merge pull requests without these things because the change may introduce breaking changes to the framework.

Feel free to re-submit your change with a thorough explanation of the feature and tests - integration tests are preferred over unit tests. Please include it's benefit to end users; the reasons it does not break any existing features; how it makes building web applications easier, etc.

Thanks!