skip lookup for get if id is nil

lib/fog/aws/models/ec2/addresses.rb

@@ -43,7 +43,9 @@ module Fog
         end
 
         def get(public_ip)
-          all(public_ip).first
+          if public_ip
+            all(public_ip).first
+          end
         rescue Fog::Errors::BadRequest
           nil
         end

lib/fog/aws/models/ec2/instances.rb

@@ -39,7 +39,9 @@ module Fog
         end
 
         def get(instance_id)
-          all(instance_id).first
+          if instance_id
+            all(instance_id).first
+          end
         rescue Fog::Errors::BadRequest
           nil
         end

lib/fog/aws/models/ec2/key_pairs.rb

@@ -37,7 +37,9 @@ module Fog
         end
 
         def get(key_name)
-          all(key_name).first
+          if key_name
+            all(key_name).first
+          end
         rescue Fog::Errors::BadRequest
           nil
         end

lib/fog/aws/models/ec2/security_groups.rb

@@ -37,7 +37,9 @@ module Fog
         end
 
         def get(group_name)
-          all(group_name).first
+          if group_name
+            all(group_name).first
+          end
         rescue Fog::Errors::BadRequest
           nil
         end

lib/fog/aws/models/ec2/snapshots.rb

@@ -43,7 +43,9 @@ module Fog
         end
 
         def get(snapshot_id)
-          all(snapshot_id).first
+          if snapshot_id
+            all(snapshot_id).first
+          end
         rescue Fog::Errors::BadRequest
           nil
         end

lib/fog/aws/models/ec2/volumes.rb

@@ -43,7 +43,9 @@ module Fog
         end
 
         def get(volume_id)
-          all(volume_id).first
+          if volume_id
+            all(volume_id).first
+          end
         rescue Fog::Errors::BadRequest
           nil
         end