Fix memory leak in error case

Bug: 37239013
Change-Id: Ic33e0f7ed946d0729efa46f69aff1a5d35e81b1e
(cherry picked from commit ab34612a31e82b713ca0ac043e14f68f3788fbda)
diff --git a/media/libstagefright/MPEG4Extractor.cpp b/media/libstagefright/MPEG4Extractor.cpp
index f42fbcf..23b36d4 100644
--- a/media/libstagefright/MPEG4Extractor.cpp
+++ b/media/libstagefright/MPEG4Extractor.cpp
@@ -1233,6 +1233,7 @@
             ALOGV("allocated pssh @ %p", pssh.data);
             ssize_t requested = (ssize_t) pssh.datalen;
             if (mDataSource->readAt(data_offset + 24, pssh.data, requested) < requested) {
+                delete[] pssh.data;
                 return ERROR_IO;
             }
             mPssh.push_back(pssh);