Revert "Revert "Add external/xdelta3 and external/syspatch""

This reverts commit 1e6287ca87.
Change-Id: Ic75df2e517db1ffd5ceed65f66576867e29bde92

default.xml

@@ -226,6 +226,7 @@
   <project path="external/strace" name="platform/external/strace" />
   <project path="external/stressapptest" name="platform/external/stressapptest" />
   <project path="external/svox" name="platform/external/svox" />
+  <project path="external/syspatch" name="platform/external/syspatch" />
   <project path="external/tagsoup" name="platform/external/tagsoup" />
   <project path="external/tcpdump" name="platform/external/tcpdump" />
   <project path="external/timezonepicker-support" name="platform/external/timezonepicker-support" />
@@ -239,6 +240,7 @@
   <project path="external/webp" name="platform/external/webp" />
   <project path="external/webrtc" name="platform/external/webrtc" groups="pdk" />
   <project path="external/wpa_supplicant_8" name="platform/external/wpa_supplicant_8" groups="pdk" />
+  <project path="external/xdelta3" name="platform/external/xdelta3" />
   <project path="external/xmlwriter" name="platform/external/xmlwriter" />
   <project path="external/xmp_toolkit" name="platform/external/xmp_toolkit" />
   <project path="external/yaffs2" name="platform/external/yaffs2" groups="pdk" />