Update for pacman 4.1, which calls prepare() automatically

PKGBUILD

@@ -8,7 +8,7 @@ pkgver=1.0.2
 _seafilever=1.5.3
 
 #The release number for the arch package, as fixes are added to the PKGBUILD, the release number will increase
-pkgrel=3
+pkgrel=4
 
 # The description of the package, should be about 80 characters long (one line)
 pkgdesc="A simple and easy-to-use C language RPC framework (including both server side & client side) based on GObject System."
@@ -23,7 +23,7 @@ url="https://github.com/haiwen/libsearpc/"
 license=('GPLv3')
 
 # Packages that your software needs to run. If the dependancy requires a minimum version number use the >= operator
-depends=('glib2>=2.16.0')
+depends=('glib2>=2.16.0' 'pacman>=4.1')
 
 # Packages that must be installed to build the software, but at not necessary to run it
 makedepends=('python2-simplejson')
@@ -48,7 +48,6 @@ prepare () {
 }
 
 build () {
-	prepare
 	cd "$srcdir/seafile-$_seafilever/$pkgname"
 	./configure --prefix=/usr PYTHON=/usr/bin/python2
 	make -j1