Fix curl-retry

* Raised the number of trys to 20, that's a better number
* Added a : and a missing space to the error msg, makes it better readable.
20 jobs for fixCurl in 3 minutes and 29 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Lint
passed #6742
lint:lint-php5.4

00:00:41

passed #6743
lint:lint-php5.6

00:00:41

passed #6558
lint:lint-php7.0

00:00:40

passed #6744
lint:lint-php7.1

00:00:47

passed #6560
lint:lint-php7.2

00:00:25

canceled #6556
lint:lint-php5.4

00:00:47

canceled #6557
lint:lint-php5.6

00:00:47

canceled #6559
lint:lint-php7.1

00:00:47

 
  Codesniffer
passed #6745
allowed to fail
codesniffer

00:00:54

canceled #6561
allowed to fail
codesniffer

 
  Unit
passed #6746
unit:testBasic

00:00:55

passed #6749
unit:testPageProperty

00:00:54

passed #6747
unit:testRead

00:00:53

passed #6748
unit:testReadAssertFail

00:00:53

passed #6750
unit:testUserProperty

00:01:01

canceled #6562
unit:testBasic

canceled #6565
unit:testPageProperty

canceled #6563
unit:testRead

canceled #6564
unit:testReadAssertFail

canceled #6566
unit:testUserProperty