build-and-provide-package: Look only for the "real" debian/control file
build-and-provide-package: Look only for the "real" debian/control file

Otherwise this breaks in a situation like that:

| % tar atf autopkgtest_2.3.5~pgdg70+1.tar.gz | grep control
| -rw-r--r-- 0/0             297 2013-09-25 08:51 source/tests/testpkg/debian/control
| -rw-r--r-- 0/0             151 2013-09-25 08:51 source/debian/tests/control
| -rw-r--r-- 0/0            1982 2013-09-25 08:51 source/debian/control

Thanks: Christoph Berg <8a0b9c1d8bf873f9527ef3eb694eb7769d75f6e7@credativ.de> for the bugreport and fix

zeha/jenkins-debian-glue,vorlock/jenkins-debian-glue,bmiklautz/jenkins-debian-glue,tonin/jenkins-debian-glue,kartikm/jenkins-debian-glue,wikimedia/operations-debs-jenkins-debian-glue,tonin/jenkins-debian-glue,mika/jenkins-debian-glue,wikimedia/operations-debs-jenkins-debian-glue,kartikm/jenkins-debian-glue,linuxmaniac/jenkins-debian-glue,bmiklautz/jenkins-debian-glue,n054/jenkins-debian-glue,mika/jenkins-debian-glue,linuxmaniac/jenkins-debian-glue,cclausen/jenkins-debian-glue,zeha/jenkins-debian-glue,jbfavre/jenkins-debian-glue,vorlock/jenkins-debian-glue,hetznerZA/jenkins-debian-glue,webtrekk-kane/jenkins-debian-glue,webtrekk-kane/jenkins-debian-glue,hashar/jenkins-debian-glue,hashar/jenkins-debian-glue,cclausen/jenkins-debian-glue,jbfavre/jenkins-debian-glue,hetznerZA/jenkins-debian-glue,n054/jenkins-debian-glue