M4=/bin/m4 for fedora:35 autoreconf github builds (#97)

Applying what we did for branch builds to the fedora github CI builds:
38a1eb4e87d4ff8c9feb6c81d72ce2addc83fbc2
diff --git a/jenkins/github/fedora.pipeline b/jenkins/github/fedora.pipeline
index 9e92e58..a12c42a 100644
--- a/jenkins/github/fedora.pipeline
+++ b/jenkins/github/fedora.pipeline
@@ -54,7 +54,7 @@
                         autoreconf_succeeded=0
                         for i in {1..5}
                         do
-                          if CONFIG_SHELL=/bin/bash autoreconf -fiv
+                          if M4=/bin/m4 CONFIG_SHELL=/bin/bash autoreconf -fiv
                           then
                             autoreconf_succeeded=1
                             break