ignore bin directory in various verification scripts

these scripts would choke in various ways on a vendored copy of go

ignoring `bin` is the correct behaviour anyway, and should speed up
running the scripts

Signed-off-by: Ashley Davis <ashley.davis@jetstack.io>

hack/verify-errexit.sh

@@ -31,7 +31,7 @@ echo "+++ validating all scripts set '-o errexit'" >&2
 if [ "$*" != "" ]; then
   args="$*"
 else
-  args=$(ls "$(pwd)" | grep -v 'bazel-' | grep -v 'external/' )
+  args=$(ls "$(pwd)" | grep -v 'bazel-' | grep -v 'external/' | grep -v 'bin' )
 fi
 
 # Gather the list of files that appear to be shell scripts.

hack/verify-goimports.sh

@@ -28,15 +28,20 @@ goimports=$(realpath "$1")
 # passing "-local" would be ideal, but it'll conflict with auto generated files ATM
 # and cause churn when we want to update those files
 #common_flags="-local github.com/cert-manager/cert-manager"
+
 common_flags=""
 
 echo "+++ running goimports" >&2
 
-output=$($goimports $common_flags -l .)
+# find all directories except bin which contain go files, and output them on a single line
+
+godirs=$(find . -not \( -path "./bin/*" -prune \) -name "*.go" | cut -d'/' -f2 | sort | uniq | tr '\n' ' ')
+
+output=$($goimports $common_flags -l $godirs)
 
 if [ ! -z "${output}" ]; then
     echo "${output}"
     echo "+++ goimports failed; the following command may fix:" >&2
-    echo "+++ $goimports $common_flags -w ." &>2
+    echo "+++ $goimports $common_flags -w $godirs" >&2
     exit 1
 fi

hack/verify_boilerplate.py

@@ -121,7 +121,7 @@ def file_extension(filename):
 SKIPPED_DIRS = [
     'Godeps', 'third_party', '_gopath', '_output',
     'external', '.git', 'vendor', '__init__.py',
-    'node_modules',
+    'node_modules', 'bin'
 ]
 
 # even when generated by bazel we will complain about some generated files
@@ -135,7 +135,16 @@ IGNORE_HEADERS = [
 
 def has_ignored_header(pathname):
     with open(pathname, 'r', encoding="utf-8") as myfile:
-        data = myfile.read()
+        try:
+            data = myfile.read()
+        except Exception as e:
+            # read() can fail if, e.g., the script tries to read a binary file;
+            # we could handle UnicodeDecodeError but if the script is recursing
+            # into a folder with binaries we probably want to know about it
+            # so print the name of the failed file and fail loudly
+            print("failed to read", pathname)
+            raise
+
         for header in IGNORE_HEADERS:
             if header in data:
                 return True