minor #4848 Fix typo: BLOG => BLOB (ifdattic)

This PR was merged into the 2.6 branch.

Discussion
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Fix typo: BLOG => BLOB

| Q             | A
| ------------- | ---
| Doc fix?      | yes
| New docs?     | no
| Applies to    | 2.6
| Fixed tickets |

Commits
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d83f005 Fix typo: BLOG => BLOB

cookbook/configuration/pdo_session_storage.rst

@@ -213,7 +213,7 @@ Example SQL Statements
     * A new session lifetime (``sess_lifetime`` by default) integer column
       needs to be added;
     * The data column (``sess_data`` by default) needs to be changed to a
-      BLOG type.
+      BLOB type.
 
     Check the SQL statements below for more details.