use the --distro option to run on various supported distro

Signed-off-by: Vasu Kulkarni <vasu@redhat.com>

diff --git a/qa/suites/rados/thrash-erasure-code-isa/supported b/qa/suites/rados/thrash-erasure-code-isa/supported
deleted file mode 120000 (symlink)
index c5d5935..0000000
--- a/qa/suites/rados/thrash-erasure-code-isa/supported
+++ /dev/null
@@ -1 +0,0 @@
-../../../distros/supported
\ No newline at end of file