xbps: merge patch from master.

Fixes the build issue seen in buildbot, returning ENXIO.

srcpkgs/xbps/patches/2f1fd70a4e.patch

@@ -0,0 +1,22 @@
+commit 2f1fd70a4e9ec65dc83a4d98dba1b3fc2be9c6ce
+Author: Juan RP <xtraeme@gmail.com>
+Date:   Fri Jun 21 17:13:06 2019 +0200
+
+    xbps_transaction_prepare: initialize trans dict!
+    
+    ... otherwise it will always return ENXIO
+
+diff --git a/lib/transaction_prepare.c b/lib/transaction_prepare.c
+index 9921127d..79a68f2a 100644
+--- lib/transaction_prepare.c
++++ lib/transaction_prepare.c
+@@ -279,6 +279,9 @@ xbps_transaction_prepare(struct xbps_handle *xhp)
+ 	unsigned int i, cnt;
+ 	int rv = 0;
+ 
++	if ((rv = xbps_transaction_init(xhp)) != 0)
++		return rv;
++
+ 	if (xhp->transd == NULL)
+ 		return ENXIO;
+ 

srcpkgs/xbps/template

@@ -1,7 +1,7 @@
 # Template file for 'xbps'
 pkgname=xbps
 version=0.55
-revision=1
+revision=2
 bootstrap=yes
 build_style=configure
 short_desc="XBPS package system utilities"