BUG/MINOR: http: fix build warning introduced with url32/url32_src

BUG/MINOR: http: fix build warning introduced with url32/url32_src

commit 39c63c5 "url32+src - like base32+src but whole url including parameters"
was missing the last argument "const char *kw", resulting in the build warning
below :

src/proto_http.c:10351:2: warning: initialization from incompatible pointer type [enabled by default]
src/proto_http.c:10351:2: warning: (near initialization for 'sample_fetch_keywords.kw[50].process') [enabled by default]
src/proto_http.c:10352:2: warning: initialization from incompatible pointer type [enabled by default]
src/proto_http.c:10352:2: warning: (near initialization for 'sample_fetch_keywords.kw[51].process') [enabled by default]

It's harmless since it's not needed there anyway.