Fix validating SAP instance number

[varkoly]

Problem

Valid SAP instance number is not recognized as valid.

• https://bugzilla.suse.com/show_bug.cgi?id=1202979
  The SAP instance number must contains 2 digits and it is in the range from 00 to 99.
  Integer numbers starting with 0 are interpreted by Ruby as octal numbers. Therefore 08 and 09 are not recognized as valid.

yast2-sap-ha: S:M:24423:276258: csync2 configuration not enabled

• https://bugzilla.suse.com/show_bug.cgi?id=1202112

Solution

Use a regex to validate the SAP instance number:
SAP_INST_NUM_REGEX = Regexp.new('^[0-9]{2}$')

During the installation csync2.socket will be started and enabled in %post.
It is not enough to enable/start csync2 in code. yast2-sap-ha will be only installed on the additional nodes, but will not be started.

[coveralls]

Pull Request Test Coverage Report for Build 3800133921

• 40 of 144 (27.78%) changed or added relevant lines in 5 files are covered.
• 1 unchanged line in 1 file lost coverage.
• Overall coverage increased (+0.2%) to 29.477%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
src/lib/sap_ha/system/watchdog.rb	0	1	0.0%
src/lib/sap_ha/semantic_checks.rb	35	38	92.11%
src/lib/sap_ha/system/local.rb	1	16	6.25%
src/lib/sap_ha/system/hana.rb	4	27	14.81%
src/clients/sap_ha.rb	0	62	0.0%

Files with Coverage Reduction	New Missed Lines	%
src/clients/sap_ha.rb	1	0%

Totals
Change from base Build 3015065937:	0.2%
Covered Lines:	1228
Relevant Lines:	4166

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💛 - Coveralls

[lslezak]

LGTM

[yast-bot]

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