pkg/kamailio/deb: don't build tlsa for xenial [skip ci]
We are getting errors on build:
> gcc -shared -g -m64 -Wl,-O2 -Wl,-E -Wl,-Bsymbolic-functions -Wl,-z,relro -pthread -rdynamic "-ldl" -Wl,-Bsymbolic-functions tls_domain.o tls_cfg.o tls_init.o tls_verify.o tls_locking.o tls_select.o tls_dump_vf.o tls_bio.o tlsa_mod.o tls_server.o tls_rpc.o tls_ct_wrq.o tls_rand.o tls_map.o tls_util.o tls_config.o -lm /usr/lib/x86_64-linux-gnu/libssl.a /usr/lib/x86_64-linux-gnu/libcrypto.a -o tlsa.so
> /usr/bin/ld: /usr/lib/x86_64-linux-gnu/libssl.a(s3_meth.o): relocation R_X86_64_32 against `.rodata' can not be used when making a shared object; recompile with -fPIC
> /usr/lib/x86_64-linux-gnu/libssl.a: error adding symbols: Bad value
> collect2: error: ld returned 1 exit status
> ../../Makefile.rules:191: recipe for target 'tlsa.so' failed