seafile-seahub: move Django-1.11.txt in package folder

Django 1.11 (host-build) is only needed for Seahub.
And won't ever be needed for anything else (hopefully).

This change moves it to the Seahub folder.

Signed-off-by: Alexandru Ardelean <ardeleanalex@gmail.com>

net/seafile-seahub/Makefile

@@ -21,7 +21,7 @@ PKG_LICENSE_FILES:=LICENSE.txt
 
 PKG_BUILD_DIR:=$(BUILD_DIR)/seahub-$(PKG_VERSION)-server
 
-HOST_PYTHON3_PACKAGE_BUILD_DEPENDS:=Django-1.11
+HOST_PYTHON3_PACKAGE_BUILD_DEPENDS:=./Django-1.11.txt
 
 PKG_BUILD_PARALLEL:=1
 PYTHON3_PKG_BUILD:=0