remove unneeded options which overwrites values from $.jgrid.inlineEdit

Hello Tony,

current version of jqGrid has the following problem: no options from `$.jgrid.inlineEdit` will be used during inline editing with `formatter: "actions"`. The problem is that `editRow` and `saveRow` will be called with object parameter having `null` options. In the case `$.extend` (like [this one](https://github.com/tonytomov/jqGrid/blob/v4.5.4/js/grid.inlinedit.js#L145-L154)) overwrite all value of `$.jgrid.inlineEdit` with `null` or other values set [here](https://github.com/tonytomov/jqGrid/blob/v4.5.4/js/jquery.fmatter.js#L265-L278). I suggest remove the most properties of `op`. After that the variable `actop` will be initialized (see [here](https://github.com/tonytomov/jqGrid/blob/v4.5.4/js/jquery.fmatter.js#L302-L313)) with some `undefined` values, but all the values will be overwritten by `$.extend` at the beginning of  `editRow` or `saveRow` (like [this one](https://github.com/tonytomov/jqGrid/blob/v4.5.4/js/grid.inlinedit.js#L145-L154)).

Best regards
Oleg