iotests: Simplify qemu-iotests-quick.sh

As of the "iotests: Allow out-of-tree run" series, the qemu-iotests may
(and should) be run directly in the build tree and will then guess the
binary paths themselves. Therefore, qemu-iotests-quick.sh does not need
to (and should not) enter the source path anymore; also, it does not
need to specify the binaries because "check" will guess them
automatically.

As a side-effect, tests using qemu may now be added to the quick group.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
diff --git a/tests/qemu-iotests-quick.sh b/tests/qemu-iotests-quick.sh
index c449e8a..8a9a4c6 100755
--- a/tests/qemu-iotests-quick.sh
+++ b/tests/qemu-iotests-quick.sh
@@ -1,16 +1,6 @@
 #!/bin/sh
 
-# We don't know which of the system emulator binaries there is (or if there is
-# any at all), so the 'quick' group doesn't contain any tests that require
-# running qemu proper. Assign a fake binary name so that qemu-iotests doesn't
-# complain about the missing binary.
-export QEMU_PROG="this_should_be_unused"
-
-export QEMU_IMG_PROG="$(pwd)/qemu-img"
-export QEMU_IO_PROG="$(pwd)/qemu-io"
-export QEMU_NBD_PROG="$(pwd)/qemu-nbd"
-
-cd $SRC_PATH/tests/qemu-iotests
+cd tests/qemu-iotests
 
 ret=0
 ./check -T -nocache -qcow2 -g quick || ret=1