squash! Wrap IllegalArgumentException thrown by Base64 decoder

Better error messages in OpenSSHKeyFileUtil and PuTTYKeyFile

src/main/java/com/hierynomus/sshj/userauth/keyprovider/OpenSSHKeyFileUtil.java

@@ -67,7 +67,7 @@ public static ParsedPubKey initPubKey(Reader publicKey) throws IOException {
             }
             throw new IOException("Public key file is blank");
         } catch (Base64DecodingException err) {
-            throw new IOException("Public Key decoding failed: " + err.getMessage(), err);
+            throw new IOException("Public key decoding failed", err);
         } finally {
             br.close();
         }

src/main/java/net/schmizz/sshj/userauth/keyprovider/PuTTYKeyFile.java

@@ -264,7 +264,7 @@ protected void parseKeyPair() throws IOException {
             }
         }
         catch (Base64DecodingException e) {
-            throw new IOException("Corrupted PuTTY key: " + e.getMessage(), e);
+            throw new IOException("PuTTY key decoding failed", e);
         }
     }