scylla-gdb.py: debug::logalloc_alignment may not exist
scylla-gdb.py: debug::logalloc_alignment may not exist

I haven't found a way to make it stay -- __attribute__((used)) is not
enough and apparently lld is going to ignore __attribute__((retain))
until at least LLVM 13.

Signed-off-by: Michael Livshin <ae60993c65de9cdf2ca07b7426c976808535d555@scylladb.com>

scylladb/scylla,scylladb/scylla,scylladb/scylla,scylladb/scylla