rest ui: use default value instead of confusing placeholder

[andybons]

Per #287, confusion could be caused by assuming that the input placeholder value ("0" in this cause) actually represents the value being passed, which isn’t true. Setting a default value to prevent this confusion in the future.

[tbg]

That's actually not the reason for #287. I entered "0", "+0", "-0" and "00" and they all end up with

[POST] 400 /kv/rest/counter/asd: could not parse int64 for increment: strconv.ParseInt: parsing "": invalid syntax

FWIW, that's Chromium right now, but I think I had FireFox at home, though I'm not sure.

[tbg]

(I wasn't able to test your commit, so your change still might have fixed it.)

[andybons]

You’re running a non-stable Chromium channel?

[tbg]

No, don't think so.

18:15 $ /usr/bin/chromium --version
Chromium 39.0.2171.71 Built on 8.0, running on Debian 8.0

[andybons]

OK. Well let’s merge this as it at least gives a better default and keep the issue open. If you find yourself in that position again, open up the Web Inspector and paste in what data is being sent with the request.

[tbg]

Yeah, go for it.
Network explorer shows a content-length 0 request. Will test again after your merge.

POST /kv/rest/counter/asd HTTP/1.1
Host: localhost:8080
Connection: keep-alive
Content-Length: 0
Accept: application/json, text/plain, */*
Origin: http://localhost:8080
User-Agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/39.0.2171.71 Safari/537.36
Content-Type: application/x-www-form-urlencoded; charset=UTF-8
Referer: http://localhost:8080/
Accept-Encoding: gzip, deflate
Accept-Language: en-US,en;q=0.8
Cookie: JSESSIONID.e3732d2c=1oqyspzpo7p0zbsv2419htjzi; JSESSIONID.176816f4=124gw4lm8dc7917ksxk6lexoqb; JSESSIONID.81daacb6=14s37wyula7b815eh42sltypc; JSESSIONID.4771515a=5lm2uvq8fkotv591zlhowv4b; JSESSIONID.8ab14d03=1bgxgykwqc1vq149f81ia2v1; JSESSIONID.f9172fe5=1haoff248m8davzk5kh2zgcb3; JSESSIONID.315000ac=17s3ztavb5uuq1o49wjwr40ka8; JSESSIONID.e2bfe0eb=xsclz18mdmof1wcgr8emg05fg; screenResolution=1920x1080