[go][build] Correct variable name to mixedCaps

Switching a variable to mixedCaps from snake_case.

Change-Id: Id78442a2344e8a251ce3b06dd98be3041d9cb6ab
Reviewed-on: https://fuchsia-review.googlesource.com/c/third_party/go/+/1023973
Reviewed-by: Oliver Newman <olivernewman@google.com>
Fuchsia-Auto-Submit: Aaron Wood <aaronwood@google.com>
Commit-Queue: Auto-Submit <auto-submit@fuchsia-infra.iam.gserviceaccount.com>
diff --git a/makeroot/makeroot.go b/makeroot/makeroot.go
index 2087d85..ebb4872 100644
--- a/makeroot/makeroot.go
+++ b/makeroot/makeroot.go
@@ -155,9 +155,9 @@
 
 					// The following files are all compiled sources and should be ignored
 					// as expected files to find in the outdir.
-					generated_sources := []string{"zdefaultcc.go", "zbootstrap.go", "zcgo.go", "zversion.go", "zzipdata.go"}
-					for _, generated_source := range generated_sources {
-						if filepath.Base(relpath) == generated_source {
+					generatedSources := []string{"zdefaultcc.go", "zbootstrap.go", "zcgo.go", "zversion.go", "zzipdata.go"}
+					for _, generatedSource := range generatedSources {
+						if filepath.Base(relpath) == generatedSource {
 							// skipping generated source file.
 							return nil
 						}