550545: MAT macOS binaries should be signed for apple's gatekeeper

Another go at removing p2 cached version of executable as it is
unsigned.

Task-Url: https://bugs.eclipse.org/bugs/show_bug.cgi?id=550545

Change-Id: Id278008d08d613cb70705dce3d5d9e582ce8e0bf

org.eclipse.mat.product/pom.xml

@@ -81,13 +81,6 @@
 									</target>
 								</configuration>
 							</execution>
-						</executions>
-					</plugin>
-					<plugin>
-						<groupId>org.apache.maven.plugins</groupId>
-						<artifactId>maven-antrun-plugin</artifactId>
-						<version>1.7</version>
-						<executions>
 							<execution>
 								<id>publish</id>
 								<phase>install</phase>