[5.3] Fix lower case model names in policy classes

[memu]

Fixes the model name variables (from lower case to camel case) when generating a policy class based on a model.

[taylorotwell]

Please give an example of what this fixes.

[memu]

If a policy class is generated based on a model, the parameters of that class methods are lower case.

php artisan make:policy ProductCategoryPolicy --model=ProductCategory

class ProductCategoryPolicy
{

    // before fix

    /**
     * Determine whether the user can view the productcategory.
     *
     * @param  App\User  $user
     * @param  App\ProductCategory  $productcategory
     * @return mixed
     */
    public function view(User $user, ProductCategory $productcategory)
    {
        //
    }


    // after fix
    // "productcategory" --> "productCategory"


    /**
     * Determine whether the user can view the productCategory.
     *
     * @param  App\User  $user
     * @param  App\ProductCategory  $productCategory
     * @return mixed
     */
    public function view(User $user, ProductCategory $productCategory)
    {
        //
    }
}