Python: Lower precision of non-header queries

cf. github/securitylab#691 (comment)

Author: tausbn

python/ql/src/experimental/Security/CWE-208/TimingAttackAgainstHash/PossibleTimingAttackAgainstHash.ql

@@ -6,7 +6,7 @@
  *              A successful attack can result in authentication bypass.
  * @kind path-problem
  * @problem.severity error
- * @precision medium
+ * @precision low
  * @id py/possible-timing-attack-against-hash
  * @tags security
  *       external/cwe/cwe-208

python/ql/src/experimental/Security/CWE-208/TimingAttackAgainstHash/TimingAttackAgainstHash.ql

@@ -6,7 +6,7 @@
  *              A successful attack can result in authentication bypass.
  * @kind path-problem
  * @problem.severity error
- * @precision high
+ * @precision low
  * @id py/timing-attack-against-hash
  * @tags security
  *       external/cwe/cwe-208

python/ql/src/experimental/Security/CWE-208/TimingAttackAgainstSensitiveInfo/PossibleTimingAttackAgainstSensitiveInfo.ql

@@ -4,7 +4,7 @@
  *              possibly allowing a timing attack to retrieve sensitive information.
  * @kind path-problem
  * @problem.severity error
- * @precision medium
+ * @precision low
  * @id py/possible-timing-attack-sensitive-info
  * @tags security
  *       external/cwe/cwe-208

python/ql/src/experimental/Security/CWE-208/TimingAttackAgainstSensitiveInfo/TimingAttackAgainstSensitiveInfo.ql

@@ -4,7 +4,7 @@
  *              possibly allowing a timing attack to retrieve sensitive information.
  * @kind path-problem
  * @problem.severity error
- * @precision high
+ * @precision low
  * @id py/timing-attack-sensitive-info
  * @tags security
  *       external/cwe/cwe-208