Update xapian dependency to 1.4.2.

The patch `xapian_no_hardcode_lz.patch` is not necessary anymore.

Fix #15.

kiwix-build.py

@@ -781,13 +781,12 @@ class UUID(Dependency):
 
 class Xapian(Dependency):
     name = "xapian-core"
-    version = "1.4.0"
+    version = "1.4.2"
 
     class Source(ReleaseDownload):
-        archive = Remotefile('xapian-core-1.4.0.tar.xz',
-                             '10584f57112aa5e9c0e8a89e251aecbf7c582097638bfee79c1fe39a8b6a6477')
-        patches = ["xapian_pkgconfig.patch",
-                   "xapian_no_hardcode_lz.patch"]
+        archive = Remotefile('xapian-core-1.4.2.tar.xz',
+                             'aec2c4352998127a2f2316218bf70f48cef0a466a87af3939f5f547c5246e1ce')
+        patches = ["xapian_pkgconfig.patch"]
 
     class Builder(MakeBuilder):
         configure_option = "--disable-sse --disable-backend-inmemory --disable-documentation"

patches/xapian_no_hardcode_lz.patch

@@ -1,34 +0,0 @@
-diff -ur xapian-core-1.4.0/bin/Makefile.mk xapian-core-1.4.0.no_lz/bin/Makefile.mk
---- xapian-core-1.4.0/bin/Makefile.mk	2016-06-25 17:36:49.000000000 +0200
-+++ xapian-core-1.4.0.no_lz/bin/Makefile.mk	2017-02-07 11:15:10.166507000 +0100
-@@ -66,7 +66,7 @@
- 	unicode/unicode-data.cc\
- 	unicode/utf8itor.cc
- 
--bin_xapian_inspect_LDADD = $(ldflags) libgetopt.la -lz
-+bin_xapian_inspect_LDADD = $(ldflags) libgetopt.la $(libxapian_la)
- 
- bin_xapian_progsrv_SOURCES = bin/xapian-progsrv.cc
- bin_xapian_progsrv_LDADD = $(ldflags) libgetopt.la $(libxapian_la)
-diff -ur xapian-core-1.4.0/Makefile.in xapian-core-1.4.0.no_lz/Makefile.in
---- xapian-core-1.4.0/Makefile.in	2016-06-25 17:39:28.000000000 +0200
-+++ xapian-core-1.4.0.no_lz/Makefile.in	2017-02-07 11:27:21.050507000 +0100
-@@ -707,7 +707,8 @@
- 	unicode/bin_xapian_inspect-unicode-data.$(OBJEXT) \
- 	unicode/bin_xapian_inspect-utf8itor.$(OBJEXT)
- bin_xapian_inspect_OBJECTS = $(am_bin_xapian_inspect_OBJECTS)
--bin_xapian_inspect_DEPENDENCIES = $(am__DEPENDENCIES_1) libgetopt.la
-+bin_xapian_inspect_DEPENDENCIES = $(am__DEPENDENCIES_1) libgetopt.la \
-+	$(libxapian_la)
- am_bin_xapian_progsrv_OBJECTS = bin/xapian-progsrv.$(OBJEXT)
- bin_xapian_progsrv_OBJECTS = $(am_bin_xapian_progsrv_OBJECTS)
- bin_xapian_progsrv_DEPENDENCIES = $(am__DEPENDENCIES_1) libgetopt.la \
-@@ -1405,7 +1406,7 @@
- 	unicode/unicode-data.cc\
- 	unicode/utf8itor.cc
- 
--bin_xapian_inspect_LDADD = $(ldflags) libgetopt.la -lz
-+bin_xapian_inspect_LDADD = $(ldflags) libgetopt.la $(libxapian_la)
- bin_xapian_progsrv_SOURCES = bin/xapian-progsrv.cc
- bin_xapian_progsrv_LDADD = $(ldflags) libgetopt.la $(libxapian_la)
- bin_xapian_replicate_SOURCES = bin/xapian-replicate.cc