Make process_info::syscalls_to_catch an std::vector

Make process_info::syscalls_to_catch an std::vector

This patch makes the syscalls_to_catch field of process_info an
std::vector<int>.  The process_info structure must now be
newed/deleted.

In handle_extended_wait, the code that handles exec events destroys the
existing process_info and creates a new one.  It moves the content of
syscalls_to_catch from the old to the new vector.  I used std::move for
that (through an intermediary variable), which should have the same
behavior as the old code.

gdb/gdbserver/ChangeLog:

	* inferiors.h (struct process_info): Add constructor, initialize
	fields..
	<syscalls_to_catch>: Change type to std::vector<int>.
	* inferiors.c (add_process): Allocate process_info with new.
	(remove_process): Free process_info with delete.
	* linux-low.c (handle_extended_wait): Adjust.
	(gdb_catching_syscalls_p, gdb_catch_this_syscall_p): Adjust.
	* server.c (handle_general_set): Adjust.