Merge pull request #1056 from pagespeed/jmarantz-no-error-on-slow-ReadFile

do not consider it a test failure to get a slow ReadFile operation.

test/nginx_system_test.sh

@@ -1309,6 +1309,7 @@ OUT=$(cat "$ERROR_LOG" \
     | grep -v "\\[error\\].*opening temp file: No such file or directory.*" \
     | grep -v "\\[error\\].*remote\.cfg.*" \
     | grep -v "\\[error\\].*Slow read operation on file.*" \
+    | grep -v "\\[error\\].*Slow ReadFile operation on file.*" \
     | grep -v "\\[error\\].*Slow write operation on file.*" \
     | grep -v "\\[warn\\].*remote\.cfg.*" \
     | grep -v "\\[warn\\].*end token not received.*" \