Revert "Implement property functions for line-cap, line-join"

src/data/bucket/line_bucket.js

@@ -96,8 +96,8 @@ class LineBucket extends Bucket {
 
     addFeature(feature: VectorTileFeature) {
         const layout = this.layers[0].layout;
-        const join = this.layers[0].getLayoutValue('line-join', {zoom: this.zoom}, feature.properties);
-        const cap = this.layers[0].getLayoutValue('line-cap', {zoom: this.zoom}, feature.properties);
+        const join = layout['line-join'];
+        const cap = layout['line-cap'];
         const miterLimit = layout['line-miter-limit'];
         const roundLimit = layout['line-round-limit'];
 

src/style-spec/reference/v8.json

@@ -535,7 +535,6 @@
       "type": "enum",
       "function": "piecewise-constant",
       "zoom-function": true,
-      "property-function": true,
       "values": {
         "butt": {
             "doc": "A cap with a squared-off end which is drawn to the exact endpoint of the line."
@@ -563,7 +562,6 @@
       "type": "enum",
       "function": "piecewise-constant",
       "zoom-function": true,
-      "property-function": true,
       "values": {
         "bevel": {
             "doc": "A join with a squared-off end which is drawn beyond the endpoint of the line at a distance of one-half of the line's width."