Fix collectors' build tags

Signed-off-by: Jeffrey Stoke <me@arhat.dev>

Author: Jeffrey Stoke

collector/drbd_linux.go

@@ -11,6 +11,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+// +build !nodrbd
+
 package collector
 
 import (

collector/filesystem_linux_test.go

@@ -11,8 +11,6 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-// +build !nofilesystem
-
 package collector
 
 import (

collector/kvm_bsd.go

@@ -11,7 +11,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-// +build !nomeminfo
+// +build !nokvm
 // +build freebsd dragonfly
 
 package collector

collector/mountstats_linux.go

@@ -11,6 +11,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+// +build !nomountstats
+
 package collector
 
 import (

collector/nfs_linux.go

@@ -11,6 +11,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+// +build !nonfs
+
 package collector
 
 import (

collector/nfsd_linux.go

@@ -11,6 +11,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+// +build !nonfsd
+
 package collector
 
 import (

collector/perf_linux.go

@@ -11,6 +11,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+// +build !noperf
+
 package collector
 
 import (

collector/schedstat_linux.go

@@ -11,6 +11,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+// +build !noshedstat
+
 package collector
 
 import (

collector/sysctl_bsd.go

@@ -12,7 +12,7 @@
 // limitations under the License.
 
 // +build freebsd dragonfly openbsd netbsd darwin
-// +build !nomeminfo
+// +build cgo
 
 package collector
 

collector/wifi_linux.go

@@ -11,6 +11,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+// +build !nowifi
+
 package collector
 
 import (