configure: fix the extra spaces in --enable-bindings

configure: fix the extra spaces in --enable-bindings

Extra spaces between the default action assignment for the feature
--enable-bindings feature, fails with:
./configure: line 12510: with_bindings: command not found

fix the issue by removing the extra spaces in the assignment.

Fixes: https://github.com/libcgroup/libcgroup/issues/133
Reported-by: @jeffmacdonald (github username)
Signed-off-by: Kamalesh Babulal <kamalesh.babulal@oracle.com>
Signed-off-by: Tom Hromatka <tom.hromatka@oracle.com>