track usage of older feature steps (#802)

* track usage of older feature steps

* remove typo whitespace

* make buildvars consistently cased

bin/steps/gdal

@@ -26,9 +26,9 @@ if (pip-grep -s requirements.txt GDAL gdal pygdal &> /dev/null) then
     mkdir -p .heroku/vendor
     # Download and extract cryptography into target vendor directory.
     curl "$VENDORED_GDAL" -s | tar zxv -C .heroku/vendor &> /dev/null
+    mcount "steps.vendor.gdal"
   fi
 
   GDAL=$(pwd)/vendor
   export GDAL
 fi
-

bin/steps/geo-libs

@@ -22,6 +22,7 @@ source "$BIN_DIR/utils"
 
 # If GDAL exists within requirements, use vendored gdal.
 if [[ "$BUILD_WITH_GEO_LIBRARIES" ]]; then
+  mcount "buildvar.BUILD_WITH_GEO_LIBRARIES"
 
   if [ ! -f ".heroku/vendor/bin/proj" ]; then
     echo "-----> Bootstrapping gdal, geos, proj."
@@ -31,9 +32,11 @@ if [[ "$BUILD_WITH_GEO_LIBRARIES" ]]; then
     curl "$VENDORED_GEOS" -s | tar zxv -C .heroku/vendor &> /dev/null
     curl "$VENDORED_PROJ" -s | tar zxv -C .heroku/vendor &> /dev/null
 
+    mcount "steps.vendor.geo_libs"
     # Copy libjasper from build image to slug.
     if [[ "$STACK" == "heroku-16" ]]; then
       cp /usr/lib/x86_64-linux-gnu/libjasper.so* ".heroku/vendor/lib/."
+      mcount "steps.vendor.libjasper"
     fi
 
   fi

bin/steps/mercurial

@@ -4,6 +4,6 @@
 if [[ -f "requirements.txt" ]]; then
 	if (grep -Fiq "hg+" requirements.txt) then
 		/app/.heroku/python/bin/pip install  mercurial | cleanup | indent
+		mcount "steps.mercurial"
 	fi
 fi
-

bin/steps/nltk

@@ -27,6 +27,8 @@ if sp-grep -s nltk; then
         python -m nltk.downloader -d "$BUILD_DIR/.heroku/python/nltk_data" "${nltk_packages[@]}" | indent
         set_env NLTK_DATA "/app/.heroku/python/nltk_data"
 
+        mcount "buildvar.NLTK_PACKAGES_DEFINITION"
+        mcount "steps.nltk"
     else
         puts-warn "'nltk.txt' not found, not downloading any corpora"
         puts-warn "Learn more: https://devcenter.heroku.com/articles/python-nltk"

bin/steps/pylibmc

@@ -29,6 +29,7 @@ if (pip-grep -s requirements.txt pylibmc &> /dev/null) then
     mkdir -p .heroku/vendor
     # Download and extract libmemcached into target vendor directory.
     curl "$VENDORED_MEMCACHED" -s | tar zxv -C .heroku/vendor &> /dev/null
+    mcount "steps.vendor.pylibmc"
   fi
 
   LIBMEMCACHED=$(pwd)/vendor