Fix null pointer dereference in file_test.cc.

The error condition was checked for, but the return statement was
missing.

Change-Id: I92f89809a7a112fdece49a2a8a8628ff2da8e0da
Reviewed-on: https://boringssl-review.googlesource.com/5610
Reviewed-by: David Benjamin <davidben@chromium.org>
Reviewed-by: Adam Langley <agl@google.com>
diff --git a/crypto/test/file_test.cc b/crypto/test/file_test.cc
index 8df6f9a..6723350 100644
--- a/crypto/test/file_test.cc
+++ b/crypto/test/file_test.cc
@@ -128,6 +128,7 @@
       const char *delimiter = FindDelimiter(buf);
       if (delimiter == nullptr) {
         fprintf(stderr, "Line %u: Could not parse attribute.\n", line_);
+        return kReadError;
       }
       std::string key = StripSpace(buf, delimiter - buf);
       std::string value = StripSpace(delimiter + 1,