Remove leftover references to files/pips/

The files/pips/* files were removed a while ago (replaced by
pip-requires in individual projects). So remove leftover code that was
dealing with that.

Change-Id: Id521a3365ab018193607389f022a25acddb49714
diff --git a/tools/build_uec_ramdisk.sh b/tools/build_uec_ramdisk.sh
index 150ecab..3ab5daf 100755
--- a/tools/build_uec_ramdisk.sh
+++ b/tools/build_uec_ramdisk.sh
@@ -98,7 +98,7 @@
 # Pre-load the image with basic environment
 if [ ! -e $image_dir/disk-primed ]; then
     cp $image_dir/disk $image_dir/disk-primed
-    $TOOLS_DIR/warm_apts_and_pips_for_uec.sh $image_dir/disk-primed
+    $TOOLS_DIR/warm_apts_for_uec.sh $image_dir/disk-primed
     $TOOLS_DIR/copy_dev_environment_to_uec.sh $image_dir/disk-primed
 fi