Prepare to use tinycore 12

Tinycore 12 requires some more RAM than its predecessor.

Change-Id: I642ccdcef43361b5648a9652d041ebb6dfe6a0e9
(cherry picked from commit 45371bfb9e)

zuul.d/ironic-python-agent-jobs.yaml

@@ -154,7 +154,7 @@
     vars:
       devstack_localrc:
         IRONIC_RAMDISK_TYPE: tinyipa
-        IRONIC_VM_SPECS_RAM: 512
+        IRONIC_VM_SPECS_RAM: 1024
 
 # used by ironic-python-agent-builder
 - job:
@@ -163,4 +163,4 @@
     vars:
       devstack_localrc:
         IRONIC_RAMDISK_TYPE: tinyipa
-        IRONIC_VM_SPECS_RAM: 512
+        IRONIC_VM_SPECS_RAM: 1024