Expand path variables for sync destination (#18)

Expand path variables for sync destination

Running commands like cdc_rsync C:\assets\* host:~/assets -vr would create a directory called ~assets. This CL expands path variables properly.

common/remote_util.cc

@@ -119,9 +119,9 @@ ProcessStartInfo RemoteUtil::BuildProcessStartInfoForSsh(
 
 ProcessStartInfo RemoteUtil::BuildProcessStartInfoForSshPortForward(
     int local_port, int remote_port, bool reverse) {
-  // (internal): Usually, one would pass in -N here, but this makes the
-  // connection terribly slow! As a workaround, don't use -N (will open a
-  // shell), but simply eat the output.
+  // Usually, one would pass in -N here, but this makes the connection terribly
+  // slow! As a workaround, don't use -N (will open a shell), but simply eat the
+  // output.
   ProcessStartInfo si = BuildProcessStartInfoForSshInternal(
       GetPortForwardingArg(local_port, remote_port, reverse) + "-n ", "");
   si.stdout_handler = [](const void*, size_t) { return absl::OkStatus(); };