Fix UserAgentClientMinorVersion. UserAgent may not always have the patch
version. So, need to parse for minor version slightly differently.
Only added comments to function 'UserAgentClientMajorVersion'

Ran the following tests

DECLARE		@UserAgent1 nvarchar(4000) = 'NuGet Command Line/2.8.4 (Microsoft Windows NT 6.3.9600.0)'
DECLARE		@UserAgent2 nvarchar(4000) = 'NuGet Command Line/2.8 '
DECLARE		@UserAgent3 nvarchar(4000) = 'NuGet Command Line/2.8 (Microsoft Windows NT 6.3.9600.0)'
DECLARE		@UserAgent4 nvarchar(4000) = 'NuGet Command Line/2.8'

SELECT		[dbo].[UserAgentClientMinorVersion-Test](@UserAgent1)
SELECT		[dbo].[UserAgentClientMinorVersion-Test](@UserAgent2)
SELECT		[dbo].[UserAgentClientMinorVersion-Test](@UserAgent3)
SELECT		[dbo].[UserAgentClientMinorVersion-Test](@UserAgent4)

SELECT		[dbo].[UserAgentClientMajorVersion-Test](@UserAgent1)
SELECT		[dbo].[UserAgentClientMajorVersion-Test](@UserAgent2)
SELECT		[dbo].[UserAgentClientMajorVersion-Test](@UserAgent3)
SELECT		[dbo].[UserAgentClientMajorVersion-Test](@UserAgent4)
As per CR, Added a lot more comments to make the SQL more readable
Merge pull request #3 from NuGet/daravind/FixUserAgentMinClientVersion

Fix method UserAgentClientMinorVersion