Improve message about failed setLoginTimeout by showing exception type

[turbanoff]

Current message about failing setLoginTimeout can be confusing.
For example when using Spring AbstractDataSource - message in logs will looks like this:

Failed to set login timeout for data source. (setLoginTimeout)

From this message it's very hard to understand what was cause of failing method.
I propose to replace e.getMessage() with e.toString() because toString will print exception class name too. And log will look like this:

Failed to set login timeout for data source. (java.lang.UnsupportedOperationException: setLoginTimeout)

[codecov]

Codecov Report

Merging #1343 into dev will decrease coverage by 0.05%.
The diff coverage is 0%.

@@             Coverage Diff             @@
##               dev    #1343      +/-   ##
===========================================
- Coverage     74.7%   74.65%   -0.06%     
+ Complexity     546      545       -1     
===========================================
  Files           23       23              
  Lines         1929     1929              
  Branches       263      263              
===========================================
- Hits          1441     1440       -1     
  Misses         345      345              
- Partials       143      144       +1

Impacted Files	Coverage Δ	Complexity Δ
src/main/java/com/zaxxer/hikari/pool/PoolBase.java	70.67% <0%> (-0.38%)	54 <0> (-1)

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