doesn't support unix homedir expansion about btcwallet

[jolan]

diff --git a/config.go b/config.go
index 29ed421..2948267 100644
--- a/config.go
+++ b/config.go
@@ -58,6 +58,20 @@ type config struct {
    ProxyPass   string `long:"proxypass" default-mask:"-" description:"Password for proxy server"`
 }

+// cleanAndExpandPath expands environement variables and leading ~ in the
+// passed path, cleans the result, and returns it.
+func cleanAndExpandPath(path string) string {
+   // Expand initial ~ to OS specific home directory.
+   if strings.HasPrefix(path, "~") {
+       homeDir := filepath.Dir(btcwalletHomeDir)
+       path = strings.Replace(path, "~", homeDir, 1)
+   }
+
+   // NOTE: The os.ExpandEnv doesn't work with Windows-style %VARIABLE%,
+   // but they variables can still be expanded via POSIX-style $VARIABLE.
+   return filepath.Clean(os.ExpandEnv(path))
+}
+
 // updateConfigWithActiveParams update the passed config with parameters
 // from the active net params if the relevant options in the passed config
 // object are the default so options specified by the user on the command line
@@ -182,6 +196,8 @@ func loadConfig() (*config, []string, error) {
    // Add default port to connect flag if missing.
    cfg.Connect = normalizeAddress(cfg.Connect, activeNetParams.btcdPort)

+   cfg.CAFile = cleanAndExpandPath(cfg.CAFile)
+
    return &cfg, remainingArgs, nil
 }