nginx-upload-module: add openssl lib dependency

When building against nginx 1.11.2+, requires additional
-lcrypto dependency. (Nginx changed crypto approach
and dependencies for openssl are no longer default)

Upstream pull request:
https://github.com/vkholodkov/nginx-upload-module/pull/93

Fixes:
http://autobuild.buildroot.net/results/e25f8ba8d8743e47a77707cf582e58477e1860e6
http://autobuild.buildroot.net/results/c4aa6e22033be934bd311cd9761f646d44618dc0
http://autobuild.buildroot.net/results/75e935d248b46df11c32c95526423a2287ac8c62



Signed-off-by: Matthew Weber <matthew.weber@rockwellcollins.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>