Fix password generation in charmed installer

Replace base64 format passwords with hex. Base64 passwords can include
chars like "/" which may cause problems when using them in sed-like
commands.

Change-Id: Id522adf40e329d8169853b5614f5ff541a174f68
Signed-off-by: David Garcia <david.garcia@canonical.com>
diff --git a/installers/charmed_install.sh b/installers/charmed_install.sh
index 24272a1..7e73dbd 100755
--- a/installers/charmed_install.sh
+++ b/installers/charmed_install.sh
@@ -316,11 +316,11 @@
 
 function generate_password_overlay() {
     # prometheus
-    web_config_password=`openssl rand -base64 16`
+    web_config_password=`openssl rand -hex 16`
     # keystone
-    keystone_db_password=`openssl rand -base64 16`
-    keystone_admin_password=`openssl rand -base64 16`
-    keystone_service_password=`openssl rand -base64 16`
+    keystone_db_password=`openssl rand -hex 16`
+    keystone_admin_password=`openssl rand -hex 16`
+    keystone_service_password=`openssl rand -hex 16`
     #  mariadb
     mariadb_password=`openssl rand -hex 16`
     mariadb_root_password=`openssl rand -hex 16`