xlators: add classification flag to some

Add classification to those translators which has `xlator_api_t`
already defined and used.

Updates: #430
Change-Id: I9d2772cb2c4ed4ab06aaa546500cf3b7d00bddac
Signed-off-by: Amar Tumballi <amarts@redhat.com>

xlators/features/cloudsync/src/cloudsync.c

@@ -1727,4 +1727,5 @@ xlator_api_t xlator_api = {
         .cbks           = &cs_cbks,
         .options        = cs_options,
         .identifier     = "cloudsync",
+        .category       = GF_TECH_PREVIEW,
 };

xlators/performance/md-cache/src/md-cache.c

@@ -3862,4 +3862,5 @@ xlator_api_t xlator_api = {
         .cbks          = &mdc_cbks,
         .options       = mdc_options,
         .identifier    = "md-cache",
+        .category      = GF_MAINTAINED,
 };

xlators/performance/nl-cache/src/nl-cache.c

@@ -869,4 +869,5 @@ xlator_api_t xlator_api = {
         .cbks          = &nlc_cbks,
         .options       = nlc_options,
         .identifier    = "nl-cache",
+        .category      = GF_TECH_PREVIEW,
 };

xlators/performance/quick-read/src/quick-read.c

@@ -1702,4 +1702,5 @@ xlator_api_t xlator_api = {
         .cbks          = &qr_cbks,
         .options       = qr_options,
         .identifier    = "quick-read",
+        .category      = GF_MAINTAINED,
 };

xlators/protocol/server/src/server.c

@@ -1849,4 +1849,5 @@ xlator_api_t xlator_api = {
         .cbks          = &server_cbks,
         .options       = server_options,
         .identifier    = "server",
+        .category      = GF_MAINTAINED,
 };