[FAB-8547] Fix ca.keyfile args typo in documents

Some documents and comment use --ca-keyfile instead of --ca.keyfile.
This patch will fix typos in following file.
- docs/source/serverconfig.rst
- docs/source/user-guide.rst
- cmd/fabric-ca-server/config.go

Change-Id: I759243b358cafa64875ba3f0b16cfcbcfe6f6849
Signed-off-by: Nao Nishijima <nao.nishijima@hal.hitachi.com>

cmd/fabric-ca-server/config.go

@@ -52,9 +52,9 @@ const (
 #      Examples:
 #      a) --port 443
 #         To set the listening port
-#      b) --ca-keyfile ../mykey.pem
+#      b) --ca.keyfile ../mykey.pem
 #         To set the "keyfile" element in the "ca" section below;
-#         note the '-' separator character.
+#         note the '.' separator character.
 #   2) environment variable
 #      Examples:
 #      a) FABRIC_CA_SERVER_PORT=443

docs/source/serverconfig.rst

@@ -15,9 +15,9 @@ Fabric-CA Server's Configuration File
     #      Examples:
     #      a) --port 443
     #         To set the listening port
-    #      b) --ca-keyfile ../mykey.pem
+    #      b) --ca.keyfile ../mykey.pem
     #         To set the "keyfile" element in the "ca" section below;
-    #         note the '-' separator character.
+    #         note the '.' separator character.
     #   2) environment variable
     #      Examples:
     #      a) FABRIC_CA_SERVER_PORT=443

docs/source/users-guide.rst

@@ -400,7 +400,7 @@ The fields are as follows:
   -  **C** is the country
 
 If custom values for the CSR are required, you may customize the configuration
-file, delete the files specified by the ``ca.certfile`` and ``ca-keyfile``
+file, delete the files specified by the ``ca.certfile`` and ``ca.keyfile``
 configuration items, and then run the ``fabric-ca-server init -b admin:adminpw``
 command again.