Keep the working directory (and umask) inherited from
the parent. Otherwise, it's impossible to control
the working directory of the daemon (from systemd, for
example).
Furthermoer, bitmonerod attempts to create logging directories and files
*in current working directory*. This fails due to permission denied and
generates a (caught, nonfatal) exception. Below is the strace with this
patch applied (so, no `chdir("/")`), showing successful opens at `log/`
relative path. Without this patch they fail (sorry, didn't save the
trace).
```
28911 getcwd("/.../bitmonero", 128) = 25
28911 stat64("/var/lib/bitmonero/.bitmonero", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
28911 stat64("/etc/bitmonerod.conf", {st_mode=S_IFREG|0644, st_size=244, ...}) = 0
28911 open("/etc/bitmonerod.conf", O_RDONLY|O_LARGEFILE) = 3
28911 open("/var/log/bitmonero/bitmonero.log", O_WRONLY|O_CREAT|O_APPEND|O_LARGEFILE, 0666) = 3
28911 stat64("log", {st_mode=S_IFDIR|0700, st_size=4096, ...}) = 0
28911 stat64("log/dbg", {st_mode=S_IFDIR|0700, st_size=4096, ...}) = 0
28911 open("log/dbg/main.log", O_WRONLY|O_CREAT|O_TRUNC|O_LARGEFILE, 0666) = 4
```
The reasoning of chdir("/") in order to prevent the daemon from holding
a filesystem in busy state is not compelling at all: the choice of
working directory for the daemon is the user's business not the
daemon's.
This prevents the intermediate thread from exiting properly, as
fork creates a child process with only one thread, so any existing
data_logger thread will not be in the child. Since this thread
sets a flag the data_logger dtor blocks on, all children threads
will hang on exit.
many RPC functions added by the daemonize changes
(and related changes on the upstream dev branch that were not merged)
were commented out (apart from return). Other than that, this *should*
work...at any rate, it builds, and that's something.
