Initial support for Fedora 21

Initial support for Fedora 21.  Add f21 to the distribution lists for
rpms, ensure "mariadb" is used over "mysqld" and enable it in the
distro check, as we have several reports of it working.

Tested with [1]

[1] http://download.fedoraproject.org/pub/fedora/linux/releases/test/21-Beta/Cloud/Images/x86_64/Fedora-Cloud-Base-20141029-21_Beta.x86_64.qcow2

Change-Id: I97cbede806e5c00363c7174fa1e9f286de96aab6

lib/databases/mysql

@@ -26,10 +26,10 @@ function cleanup_database_mysql {
         sudo rm -rf /etc/mysql
         return
     elif is_fedora; then
-        if [[ $DISTRO =~ (rhel7) ]]; then
-            MYSQL=mariadb
-        else
+        if [[ $DISTRO =~ (rhel6) ]]; then
             MYSQL=mysqld
+        else
+            MYSQL=mariadb
         fi
     elif is_suse; then
         MYSQL=mysql
@@ -54,10 +54,10 @@ function configure_database_mysql {
         my_conf=/etc/mysql/my.cnf
         mysql=mysql
     elif is_fedora; then
-        if [[ $DISTRO =~ (rhel7) ]]; then
-            mysql=mariadb
-        else
+        if [[ $DISTRO =~ (rhel6) ]]; then
             mysql=mysqld
+        else
+            mysql=mariadb
         fi
         my_conf=/etc/my.cnf
     elif is_suse; then
@@ -142,10 +142,10 @@ EOF
     fi
     # Install mysql-server
     if is_ubuntu || is_fedora; then
-        if [[ $DISTRO =~ (rhel7) ]]; then
-            install_package mariadb-server
-        else
+        if [[ $DISTRO =~ (rhel6) ]]; then
             install_package mysql-server
+        else
+            install_package mariadb-server
         fi
     elif is_suse; then
         if ! is_package_installed mariadb; then