Reduce log level of sampling error logging (#309)

* Reduce log level of target poller throwables

* Update RulePoller.java

* Update RulePoller.java

* Update TargetPoller.java

Author: willarmiros

aws-xray-recorder-sdk-core/src/main/java/com/amazonaws/xray/strategy/sampling/pollers/RulePoller.java

@@ -71,7 +71,7 @@ public void start() {
             try {
                 pollRule();
             } catch (Throwable t) {
-                logger.error("Encountered error polling GetSamplingRules: ", t);
+                logger.info("Encountered error polling GetSamplingRules: ", t);
                 // Propagate if Error so executor stops executing.
                 // TODO(anuraaga): Many Errors aren't fatal, this should probably be more restricted, e.g.
                 // https://github.com/openzipkin/brave/blob/master/brave/src/main/java/brave/internal/Throwables.java

aws-xray-recorder-sdk-core/src/main/java/com/amazonaws/xray/strategy/sampling/pollers/TargetPoller.java

@@ -66,7 +66,7 @@ public void start() {
             try {
                 pollManifest();
             } catch (Throwable t) {
-                logger.error("Encountered error polling GetSamplingTargets: ", t);
+                logger.info("Encountered error polling GetSamplingTargets: ", t);
                 // Propagate if Error so executor stops executing.
                 // TODO(anuraaga): Many Errors aren't fatal, this should probably be more restricted, e.g.
                 // https://github.com/openzipkin/brave/blob/master/brave/src/main/java/brave/internal/Throwables.java