Fix error on non-linux targets

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "iptables"
-version = "0.4.2"
+version = "0.4.3"
 authors = ["Navid Fathollahzade <[email protected]>", "Pit Kleyersburg <[email protected]>"]
 edition = "2018"
 description = "Rust bindings for iptables"

src/lib.rs

@@ -95,7 +95,7 @@ pub struct IPTables {
 /// Returns `None` because iptables only works on linux
 #[cfg(not(target_os = "linux"))]
 pub fn new(is_ipv6: bool) -> Result<IPTables, Box<dyn Error>> {
-    Err(IPTError::Other("iptables only works on Linux"))
+    Err(error_from_str("iptables only works on Linux"))
 }
 
 /// Creates a new `IPTables` Result with the command of 'iptables' if `is_ipv6` is `false`, otherwise the command is 'ip6tables'.