Edited Issue: getupdate should not be called again if count is 0 [3100]

1. Launch manage NuGet package dialog on a project where no updates are available. (I had allowedversion constraint as well)
Actual:
The first call to get the count returns 0.
and a call is made to get the list of updates.

Expected:
Since there are no updates available getupdates should not be called again to get the list of updates.


https://preview.nuget.org/api/v2/GetUpdates()/$count?packageIds='Microsoft.Web.Infrastructure%7CRouteMagic%7Celmah%7Celmah.corelibrary%7CWebActivator%7CNuGet.Server%7CNuGet.Core%7CNinject'&versions='1.0.0.0%7C1.2%7C1.2.2%7C1.2.2%7C1.5.3%7C1.8.0%7C2.2.0%7C3.0.1.10'&includePrerelease=false&includeAllVersions=false&targetFrameworks='net40'&versionConstraints='%7C%7C%7C%7C%5B1.0%2C%201.5.3%5D%7C%5B1.0%2C%201.8.0%5D%7C%7C

https://preview.nuget.org/api/v2/GetUpdates()?$orderby=DownloadCount%20desc,Id&$skip=0&$top=30&packageIds='Microsoft.Web.Infrastructure%7CRouteMagic%7Celmah%7Celmah.corelibrary%7CWebActivator%7CNuGet.Server%7CNuGet.Core%7CNinject'&versions='1.0.0.0%7C1.2%7C1.2.2%7C1.2.2%7C1.5.3%7C1.8.0%7C2.2.0%7C3.0.1.10'&includePrerelease=false&includeAllVersions=false&targetFrameworks='net40'&versionConstraints='%7C%7C%7C%7C%5B1.0%2C%201.5.3%5D%7C%5B1.0%2C%201.8.0%5D%7C%7C