Fixed a dumb bug with the data block optimizer that caused the compiler to crash if something was actually optimized

git-svn-id: https://svn.code.sf.net/p/nsis/code/NSIS/trunk@2924 212acab6-be3b-0410-9dea-997c60f758d6

Source/build.cpp

@@ -725,6 +725,7 @@ int CEXEBuild::datablock_optimize(int start_offset)
       {
         db_opt_save += this_len;
         db->resize(max(start_offset, pos + this_len));
+        db->setro(FALSE);
         return pos;
       }
     }