Compile fix with Qt 4

Change-Id: Iae87c5c9c19de1bf7fc5e4d354f96f0365315324
Reviewed-by: David Schulz <david.schulz@digia.com>
ProjectExplorer: Clean up remaining SessionManager uses

Change-Id: I170edc81cc2bcb4de4168c5ec38d3897c2e7c7e8
Reviewed-by: David Schulz <david.schulz@digia.com>
ExtensionSystem: Add missing check to autotest.

There was no check whether the plugins to be examined actually existed,
meaning the autotest would erroneously succeed if they were not at the
right location.

Change-Id: Icd230ad7ecac9852a4ba0887e278fe9e098d084b
Reviewed-by: Christian Stenger <christian.stenger@digia.com>