Clojure code cleanups

* Simplify nil equality check
* Use positive checks for (when ...) cases
* `repeatedly` can take a length 'n'
* Use `dec` to make this simple operation easier to skim read
* Replace a loop with internal conditional with `while`
* Use (when-not ...) for conditionals where positive-case is nil
* Use Clojure's own readable fn for equality checks with zero
* Use positive conditional checks (nil punning)
* nil equality checks can use the (nil? ...) fn
* Equality checks with zero can use the readable form (zero? ...)
* Simplify negative nil return condition by using (when ...)
Merge branch 'clojure-clean-up' into 1.5.x

* clojure-clean-up:
  Clojure code cleanups
Merge pull request #744 from kbarber/maint/1.5.x/improve_git_fetch_for_pr_testing

testing: Improve git fetch handling to support refspec
Merge branch '1.5.x'

* 1.5.x:
  testing: Improve git fetch handling to support refspec
  Clojure code cleanups
Move catalog/resource hash computation functions out of
scf/storage.clj and into scf/hash.clj
Moved storage utility functions out of storage.clj to prevent a cyclic
dependency between storage.clj and query.clj
Simplified string-contains?

Replaced Java .indexOf string method with .contains for clarity, added
tests to cover the function.
Extended the test for dissoc-if-nil

Added a test case for multiple keys, only some of which are nil.
Minor changes to string-contains? and string-contains?-test
Merge pull request #745 from holguinj/master

Clojure cleanup in string-contains?, add/extend tests for string-contains? and dissoc-if-nil.
Changed the storage-utils require alias from sutil -> sutils
Merge pull request #743 from senior/maint/master/scf-storage-split

Move storage utility and hashing functions out of scf/storage.clj and into their on namespaces
PDB-67 Add migration for converting hash to id for catalogs

Signed-off-by: Ken Barber <ken@bob.sh>
PDB-67 Change SQL to support ID based primary keys for catalogs

Signed-off-by: Ken Barber <ken@bob.sh>
try alternative migration

Signed-off-by: Ken Barber <ken@bob.sh>
Get the majority of tests working for pgsql and hsqldb

Signed-off-by: Ken Barber <ken@bob.sh>