Update OpenOCD package to v0.12

Author: valeros

platform.json

@@ -99,7 +99,7 @@
       "type": "debugger",
       "optional": true,
       "owner": "platformio",
-      "version": "~2.1100.0"
+      "version": "~2.1200.0"
     },
     "tool-mkspiffs": {
       "type": "uploader",