PKG_CHECK_MODULES is redundant for bash-completion

configure.ac

@@ -64,10 +64,7 @@ AC_CONFIG_FILES([src/libknot.pc
 
 # Get Bash completion scripts directory
 bash_completion_dir=""
-PKG_CHECK_MODULES([bash_completion], [bash-completion],[
-    PKG_CHECK_VAR([bash_completion_dir], [bash-completion],[],[])
-    AC_SUBST([BASH_COMPLETION_DIR], $bash_completion_dir)
-  ],[])
+PKG_CHECK_VAR([bash_completion_dir], [bash-completion],[AC_SUBST([BASH_COMPLETION_DIR], $bash_completion_dir)],[])
 AM_CONDITIONAL([HAVE_BASH_COMPLETION], [test -n "$bash_completion_dir"])
 
 # Build Knot DNS daemon