Remove deprecated staging server and fix test for QT5 at Ubuntu 19.10

[pcgomes]

Remove "staging" host if "--debug" is set. The host is wrong and setting it via "--debug" clashes with an application own debug

[drfiemost]

TestUrlBuilder stil fails after applaying this change:

********* Start testing of TestUrlBuilder *********
Config: Using QtTest library 5.15.2, Qt 5.15.2 (x86_64-little_endian-lp64 shared (dynamic) release build; by GCC 9.3.1 20201218), unknown unknown
PASS   : TestUrlBuilder::initTestCase()
PASS   : TestUrlBuilder::encode(ascii)
PASS   : TestUrlBuilder::encode(ascii alphanumeric)
PASS   : TestUrlBuilder::encode(ascii with symbols)
PASS   : TestUrlBuilder::encode(ascii with last.fm-special symbols)
FAIL!  : TestUrlBuilder::no404(Air - Radio #1) Compared values are not the same
   Actual   (getResponseCode( url )): 301
   Expected (200)                   : 200
   Loc: [/mnt/devel/projects/liblastfm/build/tests/TestUrlBuilder.h(66)]
FAIL!  : TestUrlBuilder::no404(Pink Floyd - Speak to Me / Breathe) Compared values are not the same
   Actual   (getResponseCode( url )): 301
   Expected (200)                   : 200
   Loc: [/mnt/devel/projects/liblastfm/build/tests/TestUrlBuilder.h(66)]
FAIL!  : TestUrlBuilder::no404(Radiohead - 2 + 2 = 5) Compared values are not the same
   Actual   (getResponseCode( url )): 301
   Expected (200)                   : 200
   Loc: [/mnt/devel/projects/liblastfm/build/tests/TestUrlBuilder.h(66)]
FAIL!  : TestUrlBuilder::no404(Above & Beyond - World On Fire (Maor Levi Remix)) Compared values are not the same
   Actual   (getResponseCode( url )): 301
   Expected (200)                   : 200
   Loc: [/mnt/devel/projects/liblastfm/build/tests/TestUrlBuilder.h(66)]
FAIL!  : TestUrlBuilder::test404() Compared values are not the same
   Actual   (getResponseCode( QUrl("http://www.last.fm/404") )): 301
   Expected (404)                                              : 404
   Loc: [/mnt/devel/projects/liblastfm/build/tests/TestUrlBuilder.h(84)]
PASS   : TestUrlBuilder::cleanupTestCase()
Totals: 6 passed, 5 failed, 0 skipped, 0 blacklisted, 419ms
********* Finished testing of TestUrlBuilder *********

It seems all the URLs should be switched to https by default.