cleanup: dump -- Add warning on unexpected VMA

Instead of simply dropping this dead code, put
a warning here, just to be on a safe side.
Reported-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>

cr-dump.c

@@ -1042,7 +1042,8 @@ static int finalize_core(pid_t pid, struct list_head *vma_area_list, struct cr_f
 			}
 			num_anon++;
 		} else {
-			/* skip the file shared page */
+			pr_warning("Unexpected VMA area found\n");
+			pr_info_vma(vma_area);
 			lseek(fd_pages, PAGE_SIZE, SEEK_CUR);
 		}
 	}