Add RHEL7 beta support

RHEL7 still in beta status, so it will require the FORCE option,
until the GA release.

The main notable difference from another RHEL family members, it does
not have the mysql alias for the mariadb.

Change-Id: Ic90bb6c3dd9447fc80453c3dc1adb22cdfc6226f

lib/databases/mysql

@@ -25,7 +25,11 @@ function cleanup_database_mysql {
         sudo rm -rf /var/lib/mysql
         return
     elif is_fedora; then
-        MYSQL=mysqld
+        if [[ $DISTRO =~ (rhel7) ]]; then
+            MYSQL=mariadb
+        else
+            MYSQL=mysqld
+        fi
     elif is_suse; then
         MYSQL=mysql
     else
@@ -48,8 +52,12 @@ function configure_database_mysql {
         MY_CONF=/etc/mysql/my.cnf
         MYSQL=mysql
     elif is_fedora; then
+        if [[ $DISTRO =~ (rhel7) ]]; then
+            MYSQL=mariadb
+        else
+            MYSQL=mysqld
+        fi
         MY_CONF=/etc/my.cnf
-        MYSQL=mysqld
     elif is_suse; then
         MY_CONF=/etc/my.cnf
         MYSQL=mysql
@@ -135,7 +143,11 @@ EOF
     fi
     # Install mysql-server
     if is_ubuntu || is_fedora; then
-        install_package mysql-server
+        if [[ $DISTRO =~ (rhel7) ]]; then
+            install_package mariadb-server
+        else
+            install_package mysql-server
+        fi
     elif is_suse; then
         if ! is_package_installed mariadb; then
             install_package mysql-community-server