Make runmr script use HADOOP_HOME (#72)

diff --git a/bin/runmr b/bin/runmr
index 9de164e..ee65fac 100755
--- a/bin/runmr
+++ b/bin/runmr
@@ -41,4 +41,4 @@
 "$ex_home"/bin/build
 
 export HADOOP_USE_CLIENT_CLASSLOADER=true
-yarn jar $EXAMPLES_JAR_PATH "org.apache.accumulo.examples.$1" ${*:2}
+"$HADOOP_HOME"/bin/yarn jar $EXAMPLES_JAR_PATH "org.apache.accumulo.examples.$1" ${*:2}