Fix CID 1340271, 1340272, 1340273, 1340274 (Use after free)

Signed-off-by: Stefan Weil <sw@weilnetz.de>

src/ccmain/control.cpp

@@ -1210,6 +1210,7 @@ float Tesseract::ClassifyBlobPlusOutlines(
     C_BLOB* blob, STRING* best_str) {
   C_OUTLINE_IT ol_it;
   C_OUTLINE* first_to_keep = nullptr;
+  C_BLOB* local_blob = nullptr;
   if (blob != nullptr) {
     // Add the required outlines to the blob.
     ol_it.set_to_list(blob->out_list());
@@ -1219,7 +1220,8 @@ float Tesseract::ClassifyBlobPlusOutlines(
     if (ok_outlines[i]) {
       // This outline is to be added.
       if (blob == nullptr) {
-        blob = new C_BLOB(outlines[i]);
+        local_blob = new C_BLOB(outlines[i]);
+        blob = local_blob;
         ol_it.set_to_list(blob->out_list());
       } else {
         ol_it.add_before_stay_put(outlines[i]);
@@ -1232,7 +1234,7 @@ float Tesseract::ClassifyBlobPlusOutlines(
   if (first_to_keep == nullptr) {
     // We created blob. Empty its outlines and delete it.
     for (; !ol_it.empty(); ol_it.forward()) ol_it.extract();
-    delete blob;
+    delete local_blob;
     cert = -c2;
   } else {
     // Remove the outlines that we put in.