luci-base: fix bug in util.lua in 'shellsqescape'
luci-base: fix bug in util.lua in 'shellsqescape'

Fix a bug introduced by #561

Function 'shellsqescape' calls 'gsub' with the empty result string 'res'
instead of the actual parameter 'value'. This leads into error:
.../util.lua:160: bad argument #1 to 'gsub' (string expected, got nil)

Fix error by passing the correct parameter to the function.

After the fix, the unmount button introduced by #561 finally works.

Signed-off-by: Hannu Nyman <ab53a3387de93e31696058c104e6f769cd83fd1b@iki.fi>

cshore/luci,chris5560/openwrt-luci,teslamint/luci,ollie27/openwrt_luci,rogerpueyo/luci,cappiewu/luci,LuttyYang/luci,Wedmer/luci,taiha/luci,mumuqz/luci,nmav/luci,artynet/luci,kuoruan/luci,bittorf/luci,daofeng2015/luci,jlopenwrtluci/luci,lbthomsen/openwrt-luci,cshore/luci,kuoruan/lede-luci,chris5560/openwrt-luci,chris5560/openwrt-luci,openwrt-es/openwrt-luci,daofeng2015/luci,hnyman/luci,bittorf/luci,artynet/luci,shangjiyu/luci-with-extra,Noltari/luci,taiha/luci,bittorf/luci,artynet/luci,taiha/luci,openwrt/luci,cshore-firmware/openwrt-luci,ollie27/openwrt_luci,981213/luci-1,nmav/luci,LuttyYang/luci,981213/luci-1,cappiewu/luci,openwrt/luci,shangjiyu/luci-with-extra,daofeng2015/luci,oneru/luci,Noltari/luci,cshore-firmware/openwrt-luci,cappiewu/luci,daofeng2015/luci,bittorf/luci,Wedmer/luci,kuoruan/luci,chris5560/openwrt-luci,tobiaswaldvogel/luci,teslamint/luci,wongsyrone/luci-1,cshore-firmware/openwrt-luci,nmav/luci,openwrt-es/openwrt-luci,rogerpueyo/luci,aa65535/luci,mumuqz/luci,kuoruan/lede-luci,lbthomsen/openwrt-luci,aa65535/luci,bright-things/ionic-luci,aa65535/luci,bittorf/luci,chris5560/openwrt-luci,nmav/luci,Noltari/luci,wongsyrone/luci-1,bright-things/ionic-luci,Noltari/luci,981213/luci-1,Wedmer/luci,openwrt-es/openwrt-luci,tobiaswaldvogel/luci,daofeng2015/luci,nmav/luci,oneru/luci,tobiaswaldvogel/luci,kuoruan/lede-luci,LuttyYang/luci,981213/luci-1,Wedmer/luci,shangjiyu/luci-with-extra,nmav/luci,mumuqz/luci,bittorf/luci,hnyman/luci,chris5560/openwrt-luci,mumuqz/luci,cappiewu/luci,cshore-firmware/openwrt-luci,taiha/luci,lbthomsen/openwrt-luci,Wedmer/luci,oneru/luci,aa65535/luci,taiha/luci,shangjiyu/luci-with-extra,cshore/luci,artynet/luci,wongsyrone/luci-1,lbthomsen/openwrt-luci,taiha/luci,981213/luci-1,teslamint/luci,cshore-firmware/openwrt-luci,jlopenwrtluci/luci,artynet/luci,ollie27/openwrt_luci,openwrt/luci,teslamint/luci,hnyman/luci,teslamint/luci,bright-things/ionic-luci,remakeelectric/luci,oneru/luci,Noltari/luci,remakeelectric/luci,rogerpueyo/luci,rogerpueyo/luci,teslamint/luci,remakeelectric/luci,chris5560/openwrt-luci,cshore/luci,cshore-firmware/openwrt-luci,daofeng2015/luci,remakeelectric/luci,cshore-firmware/openwrt-luci,LuttyYang/luci,artynet/luci,daofeng2015/luci,cshore/luci,rogerpueyo/luci,remakeelectric/luci,981213/luci-1,lbthomsen/openwrt-luci,nmav/luci,kuoruan/lede-luci,bright-things/ionic-luci,rogerpueyo/luci,rogerpueyo/luci,wongsyrone/luci-1,hnyman/luci,ollie27/openwrt_luci,cshore/luci,openwrt-es/openwrt-luci,wongsyrone/luci-1,cappiewu/luci,aa65535/luci,artynet/luci,cappiewu/luci,wongsyrone/luci-1,aa65535/luci,oneru/luci,aa65535/luci,shangjiyu/luci-with-extra,openwrt-es/openwrt-luci,jlopenwrtluci/luci,jlopenwrtluci/luci,tobiaswaldvogel/luci,taiha/luci,jlopenwrtluci/luci,openwrt-es/openwrt-luci,kuoruan/luci,bright-things/ionic-luci,ollie27/openwrt_luci,bittorf/luci,ollie27/openwrt_luci,hnyman/luci,tobiaswaldvogel/luci,shangjiyu/luci-with-extra,wongsyrone/luci-1,cappiewu/luci,rogerpueyo/luci,tobiaswaldvogel/luci,kuoruan/luci,bright-things/ionic-luci,mumuqz/luci,bright-things/ionic-luci,Noltari/luci,shangjiyu/luci-with-extra,cappiewu/luci,shangjiyu/luci-with-extra,Wedmer/luci,nmav/luci,Noltari/luci,LuttyYang/luci,remakeelectric/luci,Wedmer/luci,tobiaswaldvogel/luci,daofeng2015/luci,cshore/luci,hnyman/luci,artynet/luci,Noltari/luci,jlopenwrtluci/luci,openwrt/luci,bright-things/ionic-luci,mumuqz/luci,kuoruan/luci,kuoruan/lede-luci,LuttyYang/luci,remakeelectric/luci,openwrt-es/openwrt-luci,ollie27/openwrt_luci,openwrt/luci,oneru/luci,cshore/luci,openwrt-es/openwrt-luci,teslamint/luci,taiha/luci,tobiaswaldvogel/luci,remakeelectric/luci,openwrt/luci,aa65535/luci,LuttyYang/luci,hnyman/luci,Wedmer/luci,nmav/luci,kuoruan/luci,mumuqz/luci,Noltari/luci,lbthomsen/openwrt-luci,ollie27/openwrt_luci,teslamint/luci,oneru/luci,lbthomsen/openwrt-luci,cshore-firmware/openwrt-luci,wongsyrone/luci-1,bittorf/luci,mumuqz/luci,openwrt/luci,kuoruan/lede-luci,LuttyYang/luci,chris5560/openwrt-luci,kuoruan/luci,kuoruan/luci,981213/luci-1,kuoruan/lede-luci,jlopenwrtluci/luci,lbthomsen/openwrt-luci,jlopenwrtluci/luci,oneru/luci,artynet/luci,hnyman/luci,openwrt/luci,kuoruan/lede-luci