entry_point.cc: default-initialize sigaction struct
entry_point.cc: default-initialize sigaction struct

This fixes a unitialized-memory error in Valgrind.

(Note: I found this using valgrind in debug build mode (system
allocator) with sanitizers explicitly disabled)

Signed-off-by: Niek Bouman <5efb551ede8e4133b0491be23bf51c27091327c1@gmail.com>
Message-Id: <20211006090150.102017-1-5efb551ede8e4133b0491be23bf51c27091327c1@gmail.com>

scylladb/seastar,avikivity/seastar,syuu1228/seastar,syuu1228/seastar,syuu1228/seastar,scylladb/seastar,avikivity/seastar,avikivity/seastar,scylladb/seastar