Replace strings.HasPrefix with strings.Index for SuSE scanner

[flaviu-toader]

What did you implement:

Closes #515

How did you implement it:

I replaced strings.HasPrefix call with strings.Index call for the lines returned by zypper q -lu as it seems that output contains some extra bytes, confusing HasPrefix.

How can we verify it:

I verified it by scanning a SLES 11 SP4 box.

Todos:

You don't have to satisfy all of the following.

• Write tests
• Write documentation
• Check that there aren't other open pull requests for the same issue/feature
• Format your source code by make fmt
• Pass the test by make test
• Provide verification config / commands
• Enable "Allow edits from maintainers" for this PR
• Update the messages below

Is this ready for review?: yes
Is it a breaking change?: NO

[kotakanbe]

Many Thanks!!