crimson/osd: handle fatal signals

crimson/osd: handle fatal signals

seastar sets the signal handler for SIGSEGV and SIGABRT, and its signal
handler prints the stacktrace, but the the stack frames are adresses,
which are not human readable without the help of addr2line.

since crimson is linked with -rdynamic option, we have the symbols added
to the dynamic symbol table already. let print out the symbolized
addresses instead using our own stacktrace utility.

Signed-off-by: Kefu Chai <kchai@redhat.com>
(cherry picked from commit 6e26243b6db49bb9813f8b8aeade68da07dc6065)

 Conflicts:
	src/crimson/osd/main.cc