chore: small readability refactor

This is a small refactor but made it much simpler the task of reading
through the logic in these lines - also avoids some repetition.

PR-URL: #16
Credit: @ruyadorno
Close: #16
Reviewed-by: @isaacs

Author: ruyadorno

lib/content/read.js

@@ -177,7 +177,7 @@ function withContentSri (cache, integrity, fn) {
     } else {
       // Can't use race here because a generic error can happen before a ENOENT error, and can happen before a valid result
       return Promise
-        .all(sri[sri.pickAlgorithm()].map((meta) => {
+        .all(digests.map((meta) => {
           return withContentSri(cache, meta, fn)
             .catch((err) => {
               if (err.code === 'ENOENT') {
@@ -233,7 +233,7 @@ function withContentSriSync (cache, integrity, fn) {
     return fn(cpath, digests[0])
   } else {
     let lastErr = null
-    for (const meta of sri[sri.pickAlgorithm()]) {
+    for (const meta of digests) {
       try {
         return withContentSriSync(cache, meta, fn)
       } catch (err) {