Revert "Export: Prevent babel src blocks from being evaluated if org-export-babel-evaluate is nil"

This reverts commit 12d592b73223f3b0628e10f0f627447b1a312203.  When
the variable is nil, no block will be processed, which is a bug.

lisp/ox.el

@@ -2821,7 +2821,7 @@ Return code as a string."
 	 ;; added some new ones.
 	 (org-macro-initialize-templates)
 	 (org-macro-replace-all org-macro-templates)
-	 (when org-export-babel-evaluate (org-export-execute-babel-code))
+	 (org-export-execute-babel-code)
 	 ;; Update radio targets since keyword inclusion might have
 	 ;; added some more.
 	 (org-update-radio-target-regexp)