Change all instance of 'GMT epoch' to 'Unix epoch'

src/rpc/misc.cpp

@@ -57,7 +57,7 @@ UniValue getinfo(const JSONRPCRequest& request)
             "  \"proxy\": \"host:port\",     (string, optional) the proxy used by the server\n"
             "  \"difficulty\": xxxxxx,       (numeric) the current difficulty\n"
             "  \"testnet\": true|false,      (boolean) if the server is using testnet or not\n"
-            "  \"keypoololdest\": xxxxxx,    (numeric) the timestamp (seconds since GMT epoch) of the oldest pre-generated key in the key pool\n"
+            "  \"keypoololdest\": xxxxxx,    (numeric) the timestamp (seconds since Unix epoch) of the oldest pre-generated key in the key pool\n"
             "  \"keypoolsize\": xxxx,        (numeric) how many new keys are pre-generated\n"
             "  \"unlocked_until\": ttt,      (numeric) the timestamp in seconds since epoch (midnight Jan 1 1970 GMT) that the wallet is unlocked for transfers, or 0 if the wallet is locked\n"
             "  \"paytxfee\": x.xxxx,         (numeric) the transaction fee set in " + CURRENCY_UNIT + "/kB\n"

src/wallet/rpcwallet.cpp

@@ -2286,7 +2286,7 @@ UniValue getwalletinfo(const JSONRPCRequest& request)
             "  \"unconfirmed_balance\": xxx,   (numeric) the total unconfirmed balance of the wallet in " + CURRENCY_UNIT + "\n"
             "  \"immature_balance\": xxxxxx,   (numeric) the total immature balance of the wallet in " + CURRENCY_UNIT + "\n"
             "  \"txcount\": xxxxxxx,           (numeric) the total number of transactions in the wallet\n"
-            "  \"keypoololdest\": xxxxxx,      (numeric) the timestamp (seconds since GMT epoch) of the oldest pre-generated key in the key pool\n"
+            "  \"keypoololdest\": xxxxxx,      (numeric) the timestamp (seconds since Unix epoch) of the oldest pre-generated key in the key pool\n"
             "  \"keypoolsize\": xxxx,          (numeric) how many new keys are pre-generated\n"
             "  \"unlocked_until\": ttt,        (numeric) the timestamp in seconds since epoch (midnight Jan 1 1970 GMT) that the wallet is unlocked for transfers, or 0 if the wallet is locked\n"
             "  \"paytxfee\": x.xxxx,           (numeric) the transaction fee configuration, set in " + CURRENCY_UNIT + "/kB\n"