tests: fix $dir path

Some of the test cases use $dir to refer to the location of mdadm and other test binaries. But $dir was never initialized anywhere in the test sequence.

---
 test | 1 +
 1 file changed, 1 insertion(+)

index 711a3c7a2076..91b0a98d593c 100755
@@ -6,6 +6,7 @@ targetdir="/var/tmp"
 logdir="$targetdir"
 config=/tmp/mdadm.conf
 testdir=$PWD/tests
+dir=$PWD
 devlist=
 
 savelogs=0

1.8.3.1