TestCommon: Fix QuickCheck import warnings

This only appears on systems with QuickCheck >= 2.7.

For TestCommon, it happens because the QC qualified name is only used
in the conditional section.
Fixed by making the import conditional as well.

For Statistics, the `Test.Ganeti.TestCommon` import was not necessary
for QC 2.7 because there `Test.QuickCheck` already provides `counterexample`.
Fixed by giving an import list for `Test.QuickCheck`.
Signed-off-by: Niklas Hambuechen <niklash@google.com>
Reviewed-by: Klaus Aehlig <aehlig@google.com>

test/hs/Test/Ganeti/TestCommon.hs

@@ -109,7 +109,9 @@ import System.IO.Error (isDoesNotExistError)
 import System.Process (readProcessWithExitCode)
 import qualified Test.HUnit as HUnit
 import Test.QuickCheck
+#if !MIN_VERSION_QuickCheck(2,7,0)
 import qualified Test.QuickCheck as QC
+#endif
 import Test.QuickCheck.Monadic
 import qualified Text.JSON as J
 import Numeric

test/hs/Test/Ganeti/Utils/Statistics.hs

@@ -36,7 +36,7 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 module Test.Ganeti.Utils.Statistics (testUtils_Statistics) where
 
-import Test.QuickCheck
+import Test.QuickCheck (Property, forAll, choose, vectorOf)
 
 import Test.Ganeti.TestCommon
 import Test.Ganeti.TestHelper