recipes: Replace "cp -a" with "cp -R --no-dereference --preserve=mode,links"

* Using "cp -a" leaks UID of user running the builds, causing
  many QA warnings.
* See this thread for details:
  http://lists.openembedded.org/pipermail/openembedded-core/2015-November/112904.html

Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>

meta-multimedia/recipes-mkv/libebml/libebml_1.3.0.bb

@@ -19,7 +19,7 @@ do_install() {
     install -d ${D}${libdir}
     install -m 0644 libebml.a ${D}${libdir}
     install -m 0755 libebml.so.* ${D}${libdir}
-    cp -a libebml.so ${D}${libdir}
+    cp -R --no-dereference --preserve=mode,links -v libebml.so ${D}${libdir}
 
     install -d ${D}${includedir}/ebml
     for i in ../../ebml/*.h; do

meta-multimedia/recipes-mkv/libmatroska/libmatroska_1.4.1.bb

@@ -21,7 +21,7 @@ do_install() {
     install -d ${D}${libdir}
     install -m 0644 libmatroska.a ${D}${libdir}
     install -m 0755 libmatroska.so.* ${D}${libdir}
-    cp -a libmatroska.so ${D}${libdir}
+    cp -R --no-dereference --preserve=mode,links -v libmatroska.so ${D}${libdir}
 
     install -d ${D}${includedir}/matroska
     for i in ../../matroska/*.h; do