Lower aurora-scheduler jdk req. to headless.

Reviewed at https://reviews.apache.org/r/41610/
diff --git a/builder/rpm/centos-7/Dockerfile b/builder/rpm/centos-7/Dockerfile
index 174998f..a4d9dfc 100644
--- a/builder/rpm/centos-7/Dockerfile
+++ b/builder/rpm/centos-7/Dockerfile
@@ -12,6 +12,7 @@
 #
 FROM centos:7
 
+RUN yum update -y
 RUN yum install -y \
     make \
     rpm-build \
diff --git a/specs/rpm/aurora.spec b/specs/rpm/aurora.spec
index 51c5715..e2d6f81 100644
--- a/specs/rpm/aurora.spec
+++ b/specs/rpm/aurora.spec
@@ -96,7 +96,7 @@
 %if 0%{?rhel} && 0%{?rhel} < 7
 Requires:      daemonize
 %endif
-Requires:      java-%{JAVA_VERSION}
+Requires:      java-%{JAVA_VERSION}-headless
 Requires:      mesos = %{MESOS_VERSION}