Use docker official way to unset dns search

According docker official document, use 'dns_search= .' in the docker
compose file if you don't wish to set the search domain.

https://docs.docker.com/v17.09/engine/userguide/networking/default_network/configure-dns/

Signed-off-by: wang yan <wangyan@vmware.com>

make/docker-compose.chartmuseum.tpl

@@ -16,7 +16,7 @@ services:
     restart: always
     networks:
       - harbor-chartmuseum
-    dns_search: ""
+    dns_search: .
     depends_on:
       - redis
     volumes:

make/docker-compose.clair.tpl

@@ -23,7 +23,7 @@ services:
     image: goharbor/clair-photon:__clair_version__
     restart: always
     cpu_quota: 50000
-    dns_search: ""
+    dns_search: .
     depends_on:
       - postgresql
     volumes:

make/docker-compose.notary.tpl

@@ -18,7 +18,7 @@ services:
     networks:
       - notary-sig
       - harbor-notary
-    dns_search: ""
+    dns_search: .
     volumes:
       - ./common/config/notary:/etc/notary:z
     env_file:
@@ -40,7 +40,7 @@ services:
       notary-sig:
         aliases:
           - notarysigner
-    dns_search: ""
+    dns_search: .
     volumes:
       - ./common/config/notary:/etc/notary:z
     env_file:

make/docker-compose.tpl

@@ -4,7 +4,7 @@ services:
     image: goharbor/harbor-log:__version__
     container_name: harbor-log 
     restart: always
-    dns_search: ""
+    dns_search: .
     volumes:
       - /var/log/harbor/:/var/log/docker/:z
       - ./common/config/log/:/etc/logrotate.d/:z
@@ -21,7 +21,7 @@ services:
       - ./common/config/registry/:/etc/registry/:z
     networks:
       - harbor
-    dns_search: ""
+    dns_search: .
     environment:
       - GODEBUG=netdns=cgo
     depends_on:
@@ -43,7 +43,7 @@ services:
       - ./common/config/registryctl/config.yml:/etc/registryctl/config.yml:z
     networks:
       - harbor
-    dns_search: ""
+    dns_search: .
     environment:
       - GODEBUG=netdns=cgo
     depends_on:
@@ -61,7 +61,7 @@ services:
       - /data/database:/var/lib/postgresql/data:z
     networks:
       - harbor
-    dns_search: ""
+    dns_search: .
     env_file:
       - ./common/config/db/env
     depends_on:
@@ -83,7 +83,7 @@ services:
       - /data/:/data/:z
     networks:
       - harbor
-    dns_search: ""
+    dns_search: .
     depends_on:
       - log
     logging:
@@ -106,7 +106,7 @@ services:
       - /data/psc/:/etc/core/token/:z
     networks:
       - harbor
-    dns_search: ""
+    dns_search: .
     depends_on:
       - log
       - adminserver
@@ -122,7 +122,7 @@ services:
     restart: always
     networks:
       - harbor
-    dns_search: ""
+    dns_search: .
     depends_on:
       - log
       - core
@@ -143,7 +143,7 @@ services:
       - ./common/config/jobservice/config.yml:/etc/jobservice/config.yml:z
     networks:
       - harbor
-    dns_search: ""
+    dns_search: .
     depends_on:
       - redis
       - core
@@ -161,7 +161,7 @@ services:
       - /data/redis:/var/lib/redis
     networks:
       - harbor
-    dns_search: ""
+    dns_search: .
     depends_on:
       - log
     logging:
@@ -177,7 +177,7 @@ services:
       - ./common/config/nginx:/etc/nginx:z
     networks:
       - harbor
-    dns_search: ""
+    dns_search: .
     ports:
       - 80:80
       - 443:443