ape demuxer: fix segfault on memory allocation failure.

Signed-off-by: Anton Khirnov <anton@khirnov.net>
(cherry picked from commit 273aab99bf7be2bcda95dd64101c2317ee0fcb99)

Signed-off-by: Anton Khirnov <anton@khirnov.net>
diff --git a/libavformat/ape.c b/libavformat/ape.c
index 3031e47..7511d93 100644
--- a/libavformat/ape.c
+++ b/libavformat/ape.c
@@ -356,6 +356,8 @@
 
     if (ape->seektablelength > 0) {
         ape->seektable = av_malloc(ape->seektablelength);
+        if (!ape->seektable)
+            return AVERROR(ENOMEM);
         for (i = 0; i < ape->seektablelength / sizeof(uint32_t); i++)
             ape->seektable[i] = get_le32(pb);
     }