devops: build bots should do clean builds

browser_patches/checkout_build_archive_upload.sh

@@ -58,6 +58,8 @@ fi
 
 echo "-- preparing checkout"
 ./prepare_checkout.sh $BROWSER_NAME
+echo "-- cleaning"
+./$BROWSER_NAME/clean.sh
 echo "-- building"
 ./$BROWSER_NAME/build.sh
 echo "-- archiving to $ZIP_PATH"

browser_patches/firefox/clean.sh

@@ -0,0 +1,13 @@
+#!/bin/bash
+set -e
+set +x
+
+trap "cd $(pwd -P)" EXIT
+cd "$(dirname $0)"
+cd "checkout"
+
+OBJ_FOLDER=$(ls -1 | grep obj-)
+if [[ -d $OBJ_FOLDER ]]; then
+  rm -rf $OBJ_FOLDER
+fi
+

browser_patches/webkit/clean.sh

@@ -0,0 +1,9 @@
+#!/bin/bash
+set -e
+set +x
+
+trap "cd $(pwd -P)" EXIT
+cd "$(dirname $0)"
+cd "checkout"
+
+rm -rf WebKitBuild