Use plexusCompilerVersion variable

Author: akurtakov

tycho-compiler-plugin/pom.xml

@@ -90,7 +90,7 @@
 		<dependency>
 		    <groupId>org.codehaus.plexus</groupId>
 		    <artifactId>plexus-compiler-javac</artifactId>
-		    <version>2.16.2</version>
+		    <version>${plexusCompilerVersion}</version>
 		</dependency>
 	</dependencies>