Using property based lookup for Checkstyle suppressions filter.

+ This is to be maximally compatible across all plugins and scenarios
  where the Checkstyle suppressions filter can be used.

Signed-off-by: Joakim Erdfelt <joakim.erdfelt@gmail.com>

build-resources/src/main/resources/jetty-checkstyle.xml

@@ -16,7 +16,7 @@
 
   <!-- reference to suppressions filter for both eclipse and intellij checkstyle plugins -->
   <module name="SuppressionFilter">
-    <property name="file" value="${config_loc}/jetty-suppressions.xml"/>
+    <property name="file" value="${checkstyle.suppressions.file}"/>
     <property name="optional" value="true"/>
   </module>
 

build-resources/src/main/resources/jetty-suppressions.xml

@@ -5,10 +5,14 @@
   "https://checkstyle.org/dtds/suppressions_1_2.dtd">
 
 <suppressions>
+  <suppress checks="AbbreviationAsWordInNameCheck"
+    files="[/\\]src[/\\]test[/\\]java[/\\]" />
+  <suppress checks="AvoidEscapedUnicodeCharactersCheck"
+    files="[/\\]src[/\\]test[/\\]java[/\\]" />
+  <suppress checks="LocalVariableNameCheck"
+    files="[/\\]src[/\\]test[/\\]java[/\\]" />
   <suppress checks="MethodNameCheck"
     files="[/\\]src[/\\]test[/\\]java[/\\]" />
   <suppress checks="TypeNameCheck"
     files="[/\\]src[/\\]test[/\\]java[/\\]" />
-  <suppress checks="LocalVariableNameCheck"
-    files="[/\\]src[/\\]test[/\\]java[/\\]" />
 </suppressions>

pom.xml

@@ -1133,6 +1133,8 @@
               <version>3.0.0</version>
               <configuration>
                 <configLocation>jetty-checkstyle.xml</configLocation>
+                <suppressionsLocation>jetty-suppressions.xml</suppressionsLocation>
+                <suppressionsFileExpression>checkstyle.suppressions.file</suppressionsFileExpression>
               </configuration>
               <dependencies>
                 <dependency>