configure: Use uniform description for devel packages

As all other devel packages are written in the form "name devel",
use this form for libcap devel and libattr devel, too.

Signed-off-by: Stefan Weil <sw@weilnetz.de>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
diff --git a/configure b/configure
index bbf9005..293639c 100755
--- a/configure
+++ b/configure
@@ -4611,7 +4611,7 @@
       tools="$tools fsdev/virtfs-proxy-helper\$(EXESUF)"
     else
       if test "$virtfs" = yes; then
-        error_exit "VirtFS is supported only on Linux and requires libcap-devel and libattr-devel"
+        error_exit "VirtFS is supported only on Linux and requires libcap devel and libattr devel"
       fi
       virtfs=no
     fi