shill: remove use of base::JSONReader::ValueWithError error_code

The field would be deleted after libchrome r822064 urpev.
Also add parenthesis around the string literals to silence
-Wstring-concatenation.

BUG=chromium:1144735
TEST=cros_run_unit_tests --board=eve --packages shill

Change-Id: I3b817e77910f1d60036860704356fc2917c5c427
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform2/+/2586579
Tested-by: Grace Cham <hscham@chromium.org>
Reviewed-by: Hidehiko Abe <hidehiko@chromium.org>
Reviewed-by: Brian Norris <briannorris@chromium.org>
Commit-Queue: Grace Cham <hscham@chromium.org>
diff --git a/shill/eap_credentials.cc b/shill/eap_credentials.cc
index c96753f..a5df51b 100644
--- a/shill/eap_credentials.cc
+++ b/shill/eap_credentials.cc
@@ -509,8 +509,8 @@
 
     if (!json_value.value || !json_value.value->is_dict()) {
       LOG(ERROR)
-          << "Could not deserialize a subject alternative name match. Error "
-          << json_value.error_code << ": " << json_value.error_message;
+          << "Could not deserialize a subject alternative name match. Error: "
+          << json_value.error_message;
       return base::nullopt;
     }
     base::Value deserialized_value = std::move(*json_value.value);
diff --git a/shill/throttler.cc b/shill/throttler.cc
index 9cafc8f..926ba89 100644
--- a/shill/throttler.cc
+++ b/shill/throttler.cc
@@ -33,8 +33,8 @@
 const char* const Throttler::kTCThrottleUplinkCmds[] = {
     "qdisc add dev ${INTERFACE} root handle 1: htb default 11\n",
     "class add dev ${INTERFACE} parent 1: classid 1:1 htb rate ${ULRATE}\n",
-    "class add dev ${INTERFACE} parent 1:1 classid 1:11 htb rate "
-    "${ULRATE} prio 0 quantum 300\n"};
+    ("class add dev ${INTERFACE} parent 1:1 classid 1:11 htb rate ${ULRATE} "
+     "prio 0 quantum 300\n")};
 
 const char* const Throttler::kTCThrottleDownlinkCmds[] = {
     "qdisc add dev ${INTERFACE} handle ffff: ingress\n",