Fix EXTRA_BAREMETAL_OPTS

Replace only the first '=' in each item in
EXTRA_BAREMETAL_OPTS to handle multiple '='.

Change-Id: I2d4c1b664425bf35bcdbf0bda53cfda4c66b1c6d
diff --git a/stack.sh b/stack.sh
index 0f009fc..b58daf2 100755
--- a/stack.sh
+++ b/stack.sh
@@ -1082,7 +1082,7 @@
         # Define extra baremetal nova conf flags by defining the array ``EXTRA_BAREMETAL_OPTS``.
         for I in "${EXTRA_BAREMETAL_OPTS[@]}"; do
            # Attempt to convert flags to options
-           iniset $NOVA_CONF baremetal ${I//=/ }
+           iniset $NOVA_CONF baremetal ${I/=/ }
         done
 
     # Default