Use 'type' of delete action in the log_handler builder

This was a bug where the 'type' of the open action was being used rather
than using the 'type' in the delete action config.

Tested:
- Created LogHandler with the following config.
```
{
    "blob": "/log/log-blob-name",
    "handler": {
       "type": "file",
       "path": "/var/run/log-blob-file.log"
    },
    "actions": {
        "open": {
            "type": "skip"
        },
        "delete": {
            "type": "systemd",
            "unit": "log-blob-delete.service"
        }
},
```
- Checked log-blob-delete.service was run when blob was deleted

Change-Id: I2e4c783d9b159ad269ef06721d872bb8052af81c
Signed-off-by: Brennan Swanton <brennanswanton@google.com>
diff --git a/bmc/log-handler/log_handlers_builder.cpp b/bmc/log-handler/log_handlers_builder.cpp
index 902b817..d9c7fb2 100644
--- a/bmc/log-handler/log_handlers_builder.cpp
+++ b/bmc/log-handler/log_handlers_builder.cpp
@@ -90,7 +90,7 @@
             }
 
             const auto& onDelete = a.at("delete");
-            const std::string& onDeleteType = onOpen.at("type");
+            const std::string& onDeleteType = onDelete.at("type");
             if (onDeleteType == "systemd")
             {
                 pack->onDelete = std::move(buildSystemd(onDelete));