Handle jcl-over-slf4j and commons-logging better

Various dependencies we manage use commons-logging. While SLF4J is
preferred these days, it would be disruptive to exclude the
commons-logging dependency from all the managed artifacts that depend
on it, expecting all downstream consumers to know they should add
jcl-over-slf4j manually to their dependencies instead -- especially
since commons-logging includes some API not present in jcl-over-slf4j.
Better to allow the commons-logging dependencies to appear transitively,
and instead exclude jcl-over-slf4j from the one managed dependency
(jackrabbit-webdav) we have that (IMHO erroneously) depends on it.
Then, downstream projects that want to use jcl-over-slf4j instead can
themselves add it and exclude commons-logging.

See also: http://www.slf4j.org/legacy.html#jcl-over-slf4j

Author: ctrueden

pom.xml

@@ -1137,6 +1137,7 @@
 		<slf4j-jdk14.version>${slf4j.version}</slf4j-jdk14.version>
 		<slf4j-nop.version>${slf4j.version}</slf4j-nop.version>
 		<slf4j-simple.version>${slf4j.version}</slf4j-simple.version>
+		<jcl-over-slf4j.version>${slf4j.version}</jcl-over-slf4j.version>
 
 		<!-- SnakeYAML - https://bitbucket.org/asomov/snakeyaml -->
 		<snakeyaml.version>1.25</snakeyaml.version>
@@ -2941,12 +2942,6 @@
 				<groupId>org.apache.httpcomponents</groupId>
 				<artifactId>httpclient</artifactId>
 				<version>${httpclient.version}</version>
-				<exclusions>
-					<exclusion>
-						<groupId>commons-logging</groupId>
-						<artifactId>commons-logging</artifactId>
-					</exclusion>
-				</exclusions>
 			</dependency>
 			<dependency>
 				<groupId>org.apache.httpcomponents</groupId>
@@ -3410,6 +3405,18 @@
 				<groupId>org.apache.jackrabbit</groupId>
 				<artifactId>jackrabbit-webdav</artifactId>
 				<version>${jackrabbit-webdav.version}</version>
+				<exclusions>
+					<exclusion>
+						<!--
+						Conflicts with commons-logging:commons-logging.
+						If you depend on jackrabbit-webdav, add either
+						commons-logging or jcl-over-slfj to your deps.
+						See: http://www.slf4j.org/legacy.html#jcl-over-slf4j
+						-->
+						<groupId>org.slf4j</groupId>
+						<artifactId>jcl-over-slf4j</artifactId>
+					</exclusion>
+				</exclusions>
 			</dependency>
 
 			<!-- Jackson - https://github.com/FasterXML/jackson -->
@@ -3900,6 +3907,11 @@
 				<artifactId>slf4j-simple</artifactId>
 				<version>${slf4j-simple.version}</version>
 			</dependency>
+			<dependency>
+				<groupId>org.slf4j</groupId>
+				<artifactId>jcl-over-slf4j</artifactId>
+				<version>${jcl-over-slf4j.version}</version>
+			</dependency>
 
 			<!-- SnakeYAML - https://bitbucket.org/asomov/snakeyaml -->
 			<dependency>