buildbot-*.sh scripts: clean up colorful messages.

Add helper functions `msginfo`, `msgwarning`, `msgerror`, `msgnote` and
use them in the buildbot scripts.

Bug: none
Test: ran tests in chroot as described in art/test/README.chroot.md,
      observed no changes in the colored output
Change-Id: Ibd577c80ddabef2c04d4f814c46a0d70829f8946
diff --git a/tools/buildbot-cleanup-device.sh b/tools/buildbot-cleanup-device.sh
index 038ddc4..7dee149 100755
--- a/tools/buildbot-cleanup-device.sh
+++ b/tools/buildbot-cleanup-device.sh
@@ -28,16 +28,16 @@
   fi
 
   if adb shell test -d "$ART_TEST_CHROOT"; then
-    echo -e "${green}Remove entire /linkerconfig directory from chroot directory${nc}"
+    msginfo "Remove entire /linkerconfig directory from chroot directory"
     adb shell rm -rf "$ART_TEST_CHROOT/linkerconfig"
 
-    echo -e "${green}Remove entire /system directory from chroot directory${nc}"
+    msginfo "Remove entire /system directory from chroot directory"
     adb shell rm -rf "$ART_TEST_CHROOT/system"
 
-    echo -e "${green}Remove entire /data directory from chroot directory${nc}"
+    msginfo "Remove entire /data directory from chroot directory"
     adb shell rm -rf "$ART_TEST_CHROOT/data"
 
-    echo -e "${green}Remove entire chroot directory${nc}"
+    msginfo "Remove entire chroot directory"
     adb shell rmdir "$ART_TEST_CHROOT" || adb shell ls -la "$ART_TEST_CHROOT"
   fi
 else