move client_infos from httpd.h to http.c

[ChaosEngine]

Consider a fix for #257

[ChaosEngine]

Any news on this one? Still blocking build if output_http plugin is enabled

make[3]: Entering directory '/mnt/optane15GB/portage-tmp/portage/media-video/mjpg-streamer-0_pre20200524-r1/work/mjpg-streamer-85f89a8c321e799fabb1693c5d133f3fb48ee748/mjpg-streamer-experimental/_build'
[ 68%] Building C object plugins/output_http/CMakeFiles/output_http.dir/httpd.c.o
[ 72%] Building C object plugins/output_http/CMakeFiles/output_http.dir/output_http.c.o
[ 76%] Linking C shared library output_http.so
/usr/lib/gcc/x86_64-pc-linux-gnu/11.2.0/../../../../x86_64-pc-linux-gnu/bin/ld: CMakeFiles/output_http.dir/output_http.c.o:(.bss+0xa60): multiple definition of `client_infos'; CMakeFiles/output_http.dir/httpd.c.o:(.bss+0x0): first defined here
collect2: error: ld returned 1 exit status
make[3]: *** [plugins/output_http/CMakeFiles/output_http.dir/build.make:113: plugins/output_http/output_http.so] Error 1
make[3]: Leaving directory '/mnt/optane15GB/portage-tmp/portage/media-video/mjpg-streamer-0_pre20200524-r1/work/mjpg-streamer-85f89a8c321e799fabb1693c5d133f3fb48ee748/mjpg-streamer-experimental/_build'
make[2]: *** [CMakeFiles/Makefile2:374: plugins/output_http/CMakeFiles/output_http.dir/all] Error 2
make[2]: Leaving directory '/mnt/optane15GB/portage-tmp/portage/media-video/mjpg-streamer-0_pre20200524-r1/work/mjpg-streamer-85f89a8c321e799fabb1693c5d133f3fb48ee748/mjpg-streamer-experimental/_build'
make[1]: *** [Makefile:136: all] Error 2
make[1]: Leaving directory '/mnt/optane15GB/portage-tmp/portage/media-video/mjpg-streamer-0_pre20200524-r1/work/mjpg-streamer-85f89a8c321e799fabb1693c5d133f3fb48ee748/mjpg-streamer-experimental/_build'
make: *** [Makefile:19: all] Error 2

This is visible when ENABLE_HTTP_MANAGEMENT is ON:

"plugins/output_http/CMakeLists.txt" ---> add_feature_option(ENABLE_HTTP_MANAGEMENT "Enable experimental HTTP management option" ON)