Remove special provision for c9s

[mulkieran]

Closes #527

[bgurney-rh]

It's time to add some more targets to "mockbuild.sh"; something like this:

diff --git a/mockbuild_test/mockbuild.sh b/mockbuild_test/mockbuild.sh
index bdb62cf..92aedfd 100755
--- a/mockbuild_test/mockbuild.sh
+++ b/mockbuild_test/mockbuild.sh
@@ -16,11 +16,16 @@ if [ -z "$DIST_RELEASE" ]; then
 fi
 
 case $DIST_RELEASE in
-"centos-stream")
+"centos-9-stream")
        DIST="el9"
        MOCKCONFIG="/etc/mock/centos-stream-9-x86_64.cfg"
        ;;
 
+"centos-10-stream")
+       DIST="el10"
+       MOCKCONFIG="/etc/mock/centos-stream-10-x86_64.cfg"
+       ;;
+
 "fedora-rawhide")
        DIST="fc42"
        MOCKCONFIG="/etc/mock/fedora-rawhide-x86_64.cfg"
@@ -42,7 +47,7 @@ case $DIST_RELEASE in
        ;;
 
 *)
-       echo "Usage: $0 centos-stream | fedora-rawhide | fedora-next | fedora-latest | fedora-previous"
+       echo "Usage: $0 centos-9-stream | centos-10-stream | fedora-rawhide | fedora-next | fedora-latest | fedora-previous"
        exit 1
        ;;
 esac