Clang: clean up unit handling.

- Use a QSharedPointer instead of an explicitly shared pointer.
- Remove the LiveUnitManager.

Change-Id: I05bf32c1f77c17f42ee1da39f1353cff580fa6eb
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@digia.com>

src/plugins/clangcodemodel/clangcodemodel.pro

@@ -35,7 +35,6 @@ SOURCES += \
     $$PWD/unit.cpp \
     $$PWD/utils.cpp \
     $$PWD/utils_p.cpp \
-    $$PWD/liveunitsmanager.cpp \
     $$PWD/semanticmarker.cpp \
     $$PWD/diagnostic.cpp \
     $$PWD/unsavedfiledata.cpp \
@@ -58,7 +57,6 @@ HEADERS += \
     $$PWD/unit.h \
     $$PWD/utils.h \
     $$PWD/utils_p.h \
-    $$PWD/liveunitsmanager.h \
     $$PWD/semanticmarker.h \
     $$PWD/diagnostic.h \
     $$PWD/unsavedfiledata.h \