[lldbtest] Use netloc instead of hostname to look up Android device ID.

Summary:
urlparse.ParseResult.hostname has only lowercase characters even if the
input URL had uppercase characters. Since Android device IDs can have
uppercase characters as well, use urlparse.ParseResult.netloc instead
and extract the device ID from it.

This change also improves the error message when lookup of the Android
device's API fails.

Reviewers: chaoren

Reviewed By: chaoren

Subscribers: tberghammer, lldb-commits

Differential Revision: http://reviews.llvm.org/D10278

llvm-svn: 239173