[Patch] Fix GCC 5 logical-not-parentheses warnings.

[mt]

GCC 5 (5.1.0-RC-20150412) reports.

/home/haiku/haiku/haiku/src/kits/tracker/SettingsViews.cpp: In member function 'virtual void BPrivate::DesktopSettingsView::MessageReceived(BMessage*)':
/home/haiku/haiku/haiku/src/kits/tracker/SettingsViews.cpp:237:41: error: logical not is only applied to the left hand side of comparison [-Werror=logical-not-parentheses]
     !fShowDisksIconRadioButton->Value() == 1);
                                         ^
/home/haiku/haiku/haiku/src/kits/tracker/SettingsViews.cpp:270:51: error: logical not is only applied to the left hand side of comparison [-Werror=logical-not-parentheses]
     !fMountVolumesOntoDesktopRadioButton->Value() == 1);
                                                   ^
C/home/haiku/haiku/haiku/src/kits/tracker/TaskLoop.cpp: In member function 'virtual bool BPrivate::PeriodicDelayedTask::RunIfNeeded(bigtime_t)':
/home/haiku/haiku/haiku/src/kits/tracker/TaskLoop.cpp:184:19: error: logical not is only applied to the left hand side of comparison [-Werror=logical-not-parentheses]
  if (!currentTime < fRunAfter)
                   ^
/home/haiku/haiku/haiku/src/apps/screenshot/Screenshot.cpp: In member function 'status_t Screenshot::_GetActiveWindowFrame()':
/home/haiku/haiku/haiku/src/apps/screenshot/Screenshot.cpp:311:39: error: logical not is only applied to the left hand side of comparison [-Werror=logical-not-parentheses]
       && !windowInfo->show_hide_level > 0) {
                                       ^

[pulkomandy]

These have already been fixed in existing code, sorry for not merging your patch earlier.