control: Drop Build-Depends on libncurses5-dev

It's not actually supposed to be there, since libvirt only uses
ncurses indirectly through readline.

Same as upstream commit 588d2834d799

debian/control

@@ -24,7 +24,6 @@ Build-Depends:
  libgcrypt20-dev,
  libglusterfs-dev [linux-any],
  libgnutls28-dev,
- libncurses5-dev,
  libnetcf-dev (>= 1:0.2.3-3~) [linux-any],
  libnl-3-dev [linux-any],
  libnl-route-3-dev [linux-any],