Increase timeout in pipelining test

[nickva]

In CouchDB's CI the small_pipeline test intermittently fails with something like:

in function ibrowse_tests:'-small_pipeline/0-fun-5-'/1 (test/ibrowse_tests.erl, line 150)
  {line,150},
  {expression,"Counts"},
  {expected,"\n\n\n\n\n\n\n\n\n\n"},
  {value,"\n\n\n\n\n\n\n\n\t\n"}]}

Increasing the timeout a bit seems to help in local tests.

[cmullaparthi]

Thanks, the tests really need to be rewritten, but if it helps in your CI pipeline I'm happy to merge.

[nickva]

Thank you