Revert "sandbox_linux: set CCACHE_DIR as a writable path"

This reverts commit f35888e70d8b134b854531cb0c376b4fd6dbd6ef.

Reason for revert: Need additional changes

Change-Id: I6d3fd00f53a0303e5a35dc65b066d5ce65e589f3
diff --git a/ui/build/sandbox_linux.go b/ui/build/sandbox_linux.go
index 386dc55..edb3b66 100644
--- a/ui/build/sandbox_linux.go
+++ b/ui/build/sandbox_linux.go
@@ -228,10 +228,6 @@
 		sandboxArgs = append(sandboxArgs, "-N")
 	}
 
-	if ccacheDir := os.Getenv("CCACHE_DIR"); ccacheDir != "" {
-		sandboxArgs = append(sandboxArgs, "-B", ccacheDir)
-	}
-
 	// Stop nsjail from parsing arguments
 	sandboxArgs = append(sandboxArgs, "--")