Make Spack core PEP8 compliant.

share/spack/qa/run-flake8

@@ -22,9 +22,13 @@ changed=$(git diff --name-only --find-renames develop... | grep '.py$')
 
 # Add approved style exemptions to the changed packages.
 for file in $changed; do
-    if [[ $file = *package.py ]]; then
-        cp "$file" "$file~"
+    # Make a backup to restore later
+    cp "$file" "$file.sbak~"
 
+    #
+    # Exemptions for package.py files
+    #
+    if [[ $file = *package.py ]]; then
         # Exempt lines with urls and descriptions from overlong line errors.
         perl -i -pe 's/^(\s*homepage\s*=.*)$/\1  # NOQA: ignore=E501/' $file
         perl -i -pe 's/^(\s*url\s*=.*)$/\1  # NOQA: ignore=E501/' $file
@@ -36,6 +40,11 @@ for file in $changed; do
         # Exempt '@when' decorated functions from redefinition errors.
         perl -i -pe 's/^(\s*\@when\(.*\).*)$/\1  # NOQA: ignore=F811/' $file
     fi
+
+    #
+    # Exemptions for all files
+    #
+    perl -i -pe 's/^(.*(https?|file)\:.*)$/\1  # NOQA: ignore=E501/' $file
 done
 
 return_code=0
@@ -58,8 +67,8 @@ fi
 
 # Restore original package files after modifying them.
 for file in $changed; do
-    if [[ $file = *package.py ]]; then
-        mv "${file}~" "${file}"
+    if [[ -e "${file}.sbak~" ]]; then
+        mv "${file}.sbak~" "${file}"
     fi
 done