qa: only use RHEL for workload testing

It's not useful testing workloads with different distributions; it just
adds to the maintenance burden of this qa suite as distro upgrades often
break compilation of various tests.

Signed-off-by: Patrick Donnelly <pdonnell@redhat.com>
(cherry picked from commit 017ccd21e6ce58bd772ebcdcbac0e6ac1412f409)

diff --git a/qa/suites/fs/workload/distro b/qa/suites/fs/workload/distro
deleted file mode 120000 (symlink)
index 0862b44..0000000
--- a/qa/suites/fs/workload/distro
+++ /dev/null
@@ -1 +0,0 @@
-.qa/distros/supported-random-distro$
\ No newline at end of file

diff --git a/qa/suites/fs/workload/rhel_8.yaml b/qa/suites/fs/workload/rhel_8.yaml
new file mode 120000 (symlink)
index 0000000..133acf2
--- /dev/null
+++ b/qa/suites/fs/workload/rhel_8.yaml
@@ -0,0 +1 @@
+.qa/distros/all/rhel_8.yaml
\ No newline at end of file