Remove forgotten pom.xml

Issue-Ref: 3507
Issue-Url: #3507

Signed-off-by: Simon Barner <barner@fortiss.org>

org.fortiss.af3.expression/pom.xml

-<project xmlns="http://maven.apache.org/POM/4.0.0"
-  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0
-  http://maven.apache.org/maven-v4_0_0.xsd">
-
-  <modelVersion>4.0.0</modelVersion>
-  <artifactId>org.fortiss.af3.expression</artifactId>
-  <version>2.20.0-SNAPSHOT</version>
-  <packaging>eclipse-plugin</packaging>
-
-  <parent>
-    <groupId>org.fortiss.af3.bundle</groupId>
-    <artifactId>org.fortiss.af3.bundles</artifactId>
-    <version>1.0.0-SNAPSHOT</version>
-    <relativePath>../pom.xml</relativePath>
-  </parent>
-
-  <build>
-    <plugins>
-      <plugin>
-        <groupId>org.antlr</groupId>
-        <artifactId>antlr3-maven-plugin</artifactId>
-        <version>3.5.2</version>
-        <configuration>
-          <sourceDirectory>${basedir}/grammar</sourceDirectory>
-          <outputDirectory>${basedir}/generated-src/org/fortiss/af3/expression/model/parser</outputDirectory>
-        </configuration>
-        <executions>
-          <execution>
-            <phase>process-resources</phase>
-            <goals>
-              <goal>antlr</goal>
-            </goals>
-          </execution>
-        </executions>
-      </plugin>
-    </plugins>
-  </build>
-
-</project>
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