[REEF-1802] Add *.log files to .gitignore

   * Add `*.log` entry to `.gitignore`
   * Add `**/*.log` entry to exclude section of `apache-rat-plugin` in `pom.xml`

JIRA:
  [REEF-1802](https://issues.apache.org/jira/browse/REEF-1802)

Pull Request:
  This closes #1307
diff --git a/.gitignore b/.gitignore
index 1db0fc0..dcb1de0 100644
--- a/.gitignore
+++ b/.gitignore
@@ -41,11 +41,12 @@
 tmp
 *~
 \#*
+*.log
+*.sw[op]
 #
 # ----------------------------------------------------------------------
 # Unknown Files. Please clean up over time
 # ----------------------------------------------------------------------
 ml-data
 tang.conf
-*.sw[op]
 profile-*.json
diff --git a/pom.xml b/pom.xml
index 5940dad..ecdf274 100644
--- a/pom.xml
+++ b/pom.xml
@@ -286,8 +286,8 @@
                             <exclude>REEF_LOCAL_RUNTIME/**</exclude>
                             <exclude>REEF_MESOS_RUNTIME/**</exclude>
                             <exclude>REEF_STANDALONE_RUNTIME/**</exclude>
-                            <!-- JVM error logs, especially troublesome on CI servers -->
-                            <exclude>**/hs_err_*.log</exclude>
+                            <!-- Error logs -->
+                            <exclude>**/*.log</exclude>
                             <!-- The Visual Studio and Nuget build files -->
                             <exclude>**/*.sln*</exclude>
                             <exclude>**/*.vcxproj*</exclude>