Fix undefined var in HTTP headers extraction
Fix undefined var in HTTP headers extraction

theand/raven-php,getsentry/raven-php,ste93cry/sentry-php,ruudk/sentry-client,mfn/raven-php,nokitakaze/sentry-php,cpascal/raven-php,getsentry/sentry-php,patrick91/raven-php,madssj/raven-php,ManhattanPrep/raven-php,hautelook/sentry-client,getsentry/sentry-php